doc: Move Commentary above module definition.

Merges: https://codeberg.org/guix/guix/pulls/9052
Reviewed-by: Ludovic Courtès <ludo@gnu.org>
Reviewed-by: Maxim Cournoyer <maxim@guixotic.coop>
Signed-off-by: Nguyễn Gia Phong <cnx@loang.net>

235 files changed, 2050 insertions, 2031 deletions

diff --git a/build-aux/build-self.scm b/build-aux/build-self.scm
index 942cf5f5346..96a288672a8 100644
--- a/build-aux/build-self.scm
+++ b/build-aux/build-self.scm
@@ -16,6 +16,20 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; When loaded, this module returns a monadic procedure of at least one
+;;; argument: the source tree to build.  It returns a derivation that
+;;; builds it.
+;;;
+;;; This file uses modules provided by the already-installed Guix.  Those
+;;; modules may be arbitrarily old compared to the version we want to
+;;; build.  Because of that, it must rely on the smallest set of features
+;;; that are likely to be provided by the (guix) and (gnu) modules, and by
+;;; Guile itself, forever and ever.
+;;;
+;;; Code:
+
 (define-module (build-self)
   #:use-module (gnu)
   #:use-module (guix)
@@ -32,20 +46,6 @@
   #:use-module (ice-9 popen)
   #:export (build))
 
-;;; Commentary:
-;;;
-;;; When loaded, this module returns a monadic procedure of at least one
-;;; argument: the source tree to build.  It returns a derivation that
-;;; builds it.
-;;;
-;;; This file uses modules provided by the already-installed Guix.  Those
-;;; modules may be arbitrarily old compared to the version we want to
-;;; build.  Because of that, it must rely on the smallest set of features
-;;; that are likely to be provided by the (guix) and (gnu) modules, and by
-;;; Guile itself, forever and ever.
-;;;
-;;; Code:
-
 (define (date-version-string)
   "Return the current date and hour in UTC timezone, for use as a poor
 person's version identifier."
diff --git a/etc/teams/qt/qt5-manifest.scm b/etc/teams/qt/qt5-manifest.scm
index 96f13d478d6..754ba2744ab 100644
--- a/etc/teams/qt/qt5-manifest.scm
+++ b/etc/teams/qt/qt5-manifest.scm
@@ -16,8 +16,6 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
-(load "common.scm")
-
 ;;; Commentary:
 ;;;
 ;;; This manifest can be used to update the Qt 5 packages collection, via
@@ -27,4 +25,6 @@
 ;;;
 ;;; Code:
 
+(load "common.scm")
+
 (qt-packages-manifest #:major-version "5")
diff --git a/gnu.scm b/gnu.scm
index f139531ef3e..5230c68c522 100644
--- a/gnu.scm
+++ b/gnu.scm
@@ -18,6 +18,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This composite module re-exports core parts the (gnu …) public modules.
+;;;
+;;; Code:
+
 (define-module (gnu)
   #:use-module (guix i18n)
   #:use-module (guix diagnostics)
@@ -31,12 +37,6 @@
             use-service-modules
             use-system-modules))
 
-;;; Commentary:
-;;;
-;;; This composite module re-exports core parts the (gnu …) public modules.
-;;;
-;;; Code:
-
 (eval-when (eval load compile)
   (begin
     (define %public-modules
diff --git a/gnu/artwork.scm b/gnu/artwork.scm
index d3ab13b8af7..866af42a987 100644
--- a/gnu/artwork.scm
+++ b/gnu/artwork.scm
@@ -17,17 +17,17 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
-(define-module (gnu artwork)
-  #:use-module (guix packages)
-  #:use-module (guix git-download)
-  #:export (%artwork-repository))
-
 ;;; Commentary:
 ;;;
 ;;; Common place for the definition of the Guix artwork repository.
 ;;;
 ;;; Code:
 
+(define-module (gnu artwork)
+  #:use-module (guix packages)
+  #:use-module (guix git-download)
+  #:export (%artwork-repository))
+
 (define %artwork-repository
   (let ((commit "08259679a0faef63e3ba169df5b937d836bd9262"))
     (origin
diff --git a/gnu/bootloader/grub.scm b/gnu/bootloader/grub.scm
index 79b9a1cac6f..a518c565700 100644
--- a/gnu/bootloader/grub.scm
+++ b/gnu/bootloader/grub.scm
@@ -27,6 +27,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Configuration of GNU GRUB.
+;;;
+;;; Code:
+
 (define-module (gnu bootloader grub)
   #:use-module (guix build union)
   #:use-module (guix deprecation)
@@ -73,12 +79,6 @@
 
             grub-configuration))
 
-;;; Commentary:
-;;;
-;;; Configuration of GNU GRUB.
-;;;
-;;; Code:
-
 (define* (normalize-file file mount-point store-directory-prefix)
   "Strip MOUNT-POINT and prepend STORE-DIRECTORY-PREFIX, if any, to FILE, a
 G-expression or other lowerable object denoting a file name."
diff --git a/gnu/build/activation.scm b/gnu/build/activation.scm
index dbe35f41b88..516f9d86bbe 100644
--- a/gnu/build/activation.scm
+++ b/gnu/build/activation.scm
@@ -28,6 +28,14 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provides "activation" helpers.  Activation is the process that
+;;; consists in setting up system-wide files and directories so that an
+;;; 'operating-system' configuration becomes active.
+;;;
+;;; Code:
+
 (define-module (gnu build activation)
   #:use-module (gnu system accounts)
   #:use-module (gnu system privilege)
@@ -53,14 +61,6 @@
             activate-current-system
             mkdir-p/perms))
 
-;;; Commentary:
-;;;
-;;; This module provides "activation" helpers.  Activation is the process that
-;;; consists in setting up system-wide files and directories so that an
-;;; 'operating-system' configuration becomes active.
-;;;
-;;; Code:
-
 (define %skeleton-directory
   ;; Directory containing skeleton files for new accounts.
   ;; Note: keep the trailing '/' so that 'scandir' enters it.
diff --git a/gnu/build/chromium-extension.scm b/gnu/build/chromium-extension.scm
index 8171c727341..881cbbbcbc7 100644
--- a/gnu/build/chromium-extension.scm
+++ b/gnu/build/chromium-extension.scm
@@ -17,6 +17,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Tools to deal with Chromium extensions.
+;;;
+;;; Code:
+
 (define-module (gnu build chromium-extension)
   #:use-module (guix gexp)
   #:use-module (guix packages)
@@ -26,12 +32,6 @@
   #:use-module (guix build-system trivial)
   #:export (make-chromium-extension))
 
-;;; Commentary:
-;;;
-;;; Tools to deal with Chromium extensions.
-;;;
-;;; Code:
-
 (define (make-signing-key seed)
   "Return a derivation for a deterministic PKCS #8 private key using SEED."
   (computed-file
diff --git a/gnu/build/cross-toolchain.scm b/gnu/build/cross-toolchain.scm
index da9016488f7..2246f45519d 100644
--- a/gnu/build/cross-toolchain.scm
+++ b/gnu/build/cross-toolchain.scm
@@ -21,6 +21,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provides tools to build a cross-compiler.
+;;;
+;;; Code:
+
 (define-module (gnu build cross-toolchain)
   #:use-module (guix build utils)
   #:use-module (guix build gnu-build-system)
@@ -30,12 +36,6 @@
   #:use-module (ice-9 ftw)
   #:export (cross-gcc-build-phases))
 
-;;; Commentary:
-;;;
-;;; This module provides tools to build a cross-compiler.
-;;;
-;;; Code:
-
 (define %gcc-include-paths
   ;; Environment variables for header search paths.
   ;; Note: See <http://bugs.gnu.org/22186> for why not 'CPATH'.
diff --git a/gnu/build/file-systems.scm b/gnu/build/file-systems.scm
index f236efd9250..d7831767b45 100644
--- a/gnu/build/file-systems.scm
+++ b/gnu/build/file-systems.scm
@@ -26,6 +26,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This modules provides tools to deal with disk partitions, and to mount and
+;;; check file systems.
+;;;
+;;; Code:
+
 (define-module (gnu build file-systems)
   #:use-module (gnu system uuid)
   #:use-module (gnu system file-systems)
@@ -80,13 +87,6 @@
 
             swap-space->flags-bit-mask))
 
-;;; Commentary:
-;;;
-;;; This modules provides tools to deal with disk partitions, and to mount and
-;;; check file systems.
-;;;
-;;; Code:
-
 (define (system*/console program . args)
   "Run PROGRAM with ARGS in a tty on top of /dev/console.  The return value is
 as for 'system*'."
diff --git a/gnu/build/hurd-boot.scm b/gnu/build/hurd-boot.scm
index 67975bfa647..7de9f0ec63a 100644
--- a/gnu/build/hurd-boot.scm
+++ b/gnu/build/hurd-boot.scm
@@ -17,6 +17,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This modules provides tools to deal with disk partitions, and to mount and
+;;; check file systems.
+;;;
+;;; Code:
+
 (define-module (gnu build hurd-boot)
   #:use-module (system repl error-handling)
   #:autoload   (system repl repl) (start-repl)
@@ -29,12 +36,6 @@
   #:export (make-hurd-device-nodes
             boot-hurd-system))
 
-;;; Commentary:
-;;;
-;;; Utility procedures useful to boot a Hurd system.
-;;;
-;;; Code:
-
 ;; XXX FIXME c&p from linux-boot.scm
 (define (find-long-option option arguments)
   "Find OPTION among ARGUMENTS, where OPTION is something like \"--load\".
diff --git a/gnu/build/install.scm b/gnu/build/install.scm
index 58ee77d1831..df9befe058a 100644
--- a/gnu/build/install.scm
+++ b/gnu/build/install.scm
@@ -19,6 +19,15 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module supports the installation of the GNU system on a hard disk.
+;;; It is meant to be used both in a build environment (in derivations that
+;;; build VM images), and on the bare metal (when really installing the
+;;; system.)
+;;;
+;;; Code:
+
 (define-module (gnu build install)
   #:use-module (guix build syscalls)
   #:use-module (guix build utils)
@@ -33,15 +42,6 @@
             mount-cow-store
             unmount-cow-store))
 
-;;; Commentary:
-;;;
-;;; This module supports the installation of the GNU system on a hard disk.
-;;; It is meant to be used both in a build environment (in derivations that
-;;; build VM images), and on the bare metal (when really installing the
-;;; system.)
-;;;
-;;; Code:
-
 (define (install-boot-config bootcfg bootcfg-location mount-point)
   "Atomically copy BOOTCFG into BOOTCFG-LOCATION on the MOUNT-POINT.  Note
 that the caller must make sure that BOOTCFG is registered as a GC root so
diff --git a/gnu/build/linux-boot.scm b/gnu/build/linux-boot.scm
index e0743eae55a..c1a294db18c 100644
--- a/gnu/build/linux-boot.scm
+++ b/gnu/build/linux-boot.scm
@@ -20,6 +20,15 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Utility procedures useful in a Linux initial RAM disk (initrd).  Note that
+;;; many of these use procedures not yet available in vanilla Guile (`mount',
+;;; `load-linux-module', etc.); these are provided by a Guile patch used in
+;;; the GNU distribution.
+;;;
+;;; Code:
+
 (define-module (gnu build linux-boot)
   #:use-module (rnrs io ports)
   #:use-module (system repl error-handling)
@@ -67,15 +76,6 @@
 
             read-linux-consoles))
 
-;;; Commentary:
-;;;
-;;; Utility procedures useful in a Linux initial RAM disk (initrd).  Note that
-;;; many of these use procedures not yet available in vanilla Guile (`mount',
-;;; `load-linux-module', etc.); these are provided by a Guile patch used in
-;;; the GNU distribution.
-;;;
-;;; Code:
-
 (define* (mount-essential-file-systems #:key (root "/"))
   "Mount /dev, /proc, and /sys under ROOT."
   (define (scope dir)
diff --git a/gnu/build/linux-initrd.scm b/gnu/build/linux-initrd.scm
index bb2ed0db0c7..559f02fc2a0 100644
--- a/gnu/build/linux-initrd.scm
+++ b/gnu/build/linux-initrd.scm
@@ -16,6 +16,14 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Tools to create Linux initial RAM disks ("initrds").  Initrds are
+;;; essentially gzipped cpio archives, with a '/init' executable that the
+;;; kernel runs at boot time.
+;;;
+;;; Code:
+
 (define-module (gnu build linux-initrd)
   #:use-module ((guix cpio) #:prefix cpio:)
   #:use-module (guix build utils)
@@ -27,14 +35,6 @@
   #:export (write-cpio-archive
             build-initrd))
 
-;;; Commentary:
-;;;
-;;; Tools to create Linux initial RAM disks ("initrds").  Initrds are
-;;; essentially gzipped cpio archives, with a '/init' executable that the
-;;; kernel runs at boot time.
-;;;
-;;; Code:
-
 (define* (write-cpio-archive output directory
                              #:key
                              (compress? #t)
diff --git a/gnu/build/linux-modules.scm b/gnu/build/linux-modules.scm
index 6bf71100e49..ae0137e1c12 100644
--- a/gnu/build/linux-modules.scm
+++ b/gnu/build/linux-modules.scm
@@ -20,6 +20,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Tools to deal with Linux kernel modules.
+;;;
+;;; Code:
+
 (define-module (gnu build linux-modules)
   #:use-module (guix elf)
   #:use-module (guix glob)
@@ -78,12 +84,6 @@
 
             make-linux-module-directory))
 
-;;; Commentary:
-;;;
-;;; Tools to deal with Linux kernel modules.
-;;;
-;;; Code:
-
 (define current-module-debugging-port
   (make-parameter (%make-void-port "w")))
 
diff --git a/gnu/build/marionette.scm b/gnu/build/marionette.scm
index 015fc8a98b7..b6d4ec0de9c 100644
--- a/gnu/build/marionette.scm
+++ b/gnu/build/marionette.scm
@@ -19,6 +19,17 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Instrumentation tools for QEMU virtual machines (VMs).  A "marionette" is
+;;; essentially a VM (a QEMU instance) with its monitor connected to a
+;;; Unix-domain socket, and with a REPL inside the guest listening on a
+;;; virtual console, which is itself connected to the host via a Unix-domain
+;;; socket--these are the marionette's strings, connecting it to the almighty
+;;; puppeteer.
+;;;
+;;; Code:
+
 (define-module (gnu build marionette)
   #:use-module (srfi srfi-9)
   #:use-module (srfi srfi-26)
@@ -44,17 +55,6 @@
             system-test-runner
             qemu-command))
 
-;;; Commentary:
-;;;
-;;; Instrumentation tools for QEMU virtual machines (VMs).  A "marionette" is
-;;; essentially a VM (a QEMU instance) with its monitor connected to a
-;;; Unix-domain socket, and with a REPL inside the guest listening on a
-;;; virtual console, which is itself connected to the host via a Unix-domain
-;;; socket--these are the marionette's strings, connecting it to the almighty
-;;; puppeteer.
-;;;
-;;; Code:
-
 (define-record-type <marionette>
   (marionette command pid monitor repl)
   marionette?
diff --git a/gnu/build/secret-service.scm b/gnu/build/secret-service.scm
index 5447563cd94..0c8a0c7677b 100644
--- a/gnu/build/secret-service.scm
+++ b/gnu/build/secret-service.scm
@@ -17,6 +17,15 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Utility procedures for copying secrets into a VM.
+;;;
+;;; Note: This code runs within the 'shepherd' process, hence the use of
+;;; Fibers.
+;;;
+;;; Code:
+
 (define-module (gnu build secret-service)
   #:autoload   (fibers io-wakeup) (wait-until-port-readable-operation)
   #:autoload   (fibers operations) (perform-operation
@@ -33,15 +42,6 @@
   #:export (secret-service-receive-secrets
             secret-service-send-secrets))
 
-;;; Commentary:
-;;;
-;;; Utility procedures for copying secrets into a VM.
-;;;
-;;; Note: This code runs within the 'shepherd' process, hence the use of
-;;; Fibers.
-;;;
-;;; Code:
-
 (define-syntax log
   (lambda (s)
     "Log the given message."
diff --git a/gnu/build/shepherd.scm b/gnu/build/shepherd.scm
index 4ead27be0be..26f75e5d533 100644
--- a/gnu/build/shepherd.scm
+++ b/gnu/build/shepherd.scm
@@ -19,6 +19,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provides extensions to the GNU Shepherd.  In particular, it
+;;; provides a helper to start services in a container.
+;;;
+;;; Code:
+
 (define-module (gnu build shepherd)
   #:use-module (gnu system file-systems)
   #:use-module (gnu build linux-container)
@@ -35,13 +42,6 @@
   #:export (default-mounts
             fork+exec-command/container))
 
-;;; Commentary:
-;;;
-;;; This module provides extensions to the GNU Shepherd.  In particular, it
-;;; provides a helper to start services in a container.
-;;;
-;;; Code:
-
 (define (clean-up file)
   (when file
     (catch 'system-error
diff --git a/gnu/ci.scm b/gnu/ci.scm
index a55dfc2a5f3..83f3ff21e34 100644
--- a/gnu/ci.scm
+++ b/gnu/ci.scm
@@ -20,6 +20,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This file defines build jobs for Cuirass.
+;;;
+;;; Code:
+
 (define-module (gnu ci)
   #:use-module (guix build-system channel)
   #:use-module (guix config)
@@ -82,12 +88,6 @@
             arguments->systems
             cuirass-jobs))
 
-;;; Commentary:
-;;;
-;;; This file defines build jobs for Cuirass.
-;;;
-;;; Code:
-
 (define* (derivation->job name drv
                           #:key
                           (max-silent-time 3600)
diff --git a/gnu/home.scm b/gnu/home.scm
index f0dd4a19273..40abe49191e 100644
--- a/gnu/home.scm
+++ b/gnu/home.scm
@@ -17,6 +17,14 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provides a <home-environment> record for managing
+;;; per-user packages and configuration files in the similar way as
+;;; <operating-system> do for system packages and configuration files.
+;;;
+;;; Code:
+
 (define-module (gnu home)
   #:use-module (gnu home services)
   #:use-module (gnu home services symlink-manager)
@@ -50,14 +58,6 @@
 
             %base-home-services))
 
-;;; Comment:
-;;;
-;;; This module provides a <home-environment> record for managing
-;;; per-user packages and configuration files in the similar way as
-;;; <operating-system> do for system packages and configuration files.
-;;;
-;;; Code:
-
 (define-record-type* <home-environment> home-environment
   make-home-environment
   home-environment?
diff --git a/gnu/home/services.scm b/gnu/home/services.scm
index f7d0ff08228..06f872e6460 100644
--- a/gnu/home/services.scm
+++ b/gnu/home/services.scm
@@ -20,6 +20,59 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module is similar to (gnu system services) module, but
+;;; provides Home Services, which are supposed to be used for building
+;;; home-environment.
+;;;
+;;; Home Services use the same extension as System Services.  Consult
+;;; (gnu system services) module or manual for more information.
+;;;
+;;; home-service-type is a root of home services DAG.
+;;;
+;;; home-profile-service-type is almost the same as profile-service-type, at least
+;;; for now.
+;;;
+;;; home-environment-variables-service-type generates a @file{setup-environment}
+;;; shell script, which is expected to be sourced by login shell or other program,
+;;; which starts early and spawns all other processes.  Home services for shells
+;;; automatically add code for sourcing this file, if person do not use those home
+;;; services they have to source this script manually in their's shell *profile
+;;; file (details described in the manual).
+;;;
+;;; home-files-service-type is similar to etc-service-type, but doesn't extend
+;;; home-activation, because deploy mechanism for config files is pluggable
+;;; and can be different for different home environments: The default one is
+;;; called symlink-manager, which creates links for various dotfiles and xdg
+;;; configuration files to store, but is possible to implement alternative
+;;; approaches like read-only home from Julien's guix-home-manager.
+;;;
+;;; home-run-on-first-login-service-type provides an @file{on-first-login} guile
+;;; script, which runs provided gexps once, when user makes first login.  It can
+;;; be used to start user's Shepherd and maybe some other process.  It relies on
+;;; assumption that /run/user/$UID will be created on login by some login
+;;; manager (elogind for example).
+;;;
+;;; home-activation-service-type provides an @file{activate} guile script, which
+;;; do three main things:
+;;;
+;;; - Sets environment variables to the values declared in
+;;; @file{setup-environment} shell script.  It's necessary, because user can set
+;;; for example XDG_CONFIG_HOME and it should be respected by activation gexp of
+;;; symlink-manager.
+;;;
+;;; - Sets GUIX_NEW_HOME and possibly GUIX_OLD_HOME vars to paths in the store.
+;;; Later those variables can be used by activation gexps, for example by
+;;; symlink-manager or run-on-change services.
+;;;
+;;; - Run all activation gexps provided by other home services.
+;;;
+;;; home-run-on-change-service-type allows to trigger actions during
+;;; activation if file or directory specified by pattern is changed.
+;;;
+;;; Code:
+
 (define-module (gnu home services)
   #:use-module (gnu services)
   #:use-module ((gnu packages package-management) #:select (guix))
@@ -81,59 +134,6 @@
                for-home
                for-home?))
 
-;;; Comment:
-;;;
-;;; This module is similar to (gnu system services) module, but
-;;; provides Home Services, which are supposed to be used for building
-;;; home-environment.
-;;;
-;;; Home Services use the same extension as System Services.  Consult
-;;; (gnu system services) module or manual for more information.
-;;;
-;;; home-service-type is a root of home services DAG.
-;;;
-;;; home-profile-service-type is almost the same as profile-service-type, at least
-;;; for now.
-;;;
-;;; home-environment-variables-service-type generates a @file{setup-environment}
-;;; shell script, which is expected to be sourced by login shell or other program,
-;;; which starts early and spawns all other processes.  Home services for shells
-;;; automatically add code for sourcing this file, if person do not use those home
-;;; services they have to source this script manually in their's shell *profile
-;;; file (details described in the manual).
-;;;
-;;; home-files-service-type is similar to etc-service-type, but doesn't extend
-;;; home-activation, because deploy mechanism for config files is pluggable
-;;; and can be different for different home environments: The default one is
-;;; called symlink-manager, which creates links for various dotfiles and xdg
-;;; configuration files to store, but is possible to implement alternative
-;;; approaches like read-only home from Julien's guix-home-manager.
-;;;
-;;; home-run-on-first-login-service-type provides an @file{on-first-login} guile
-;;; script, which runs provided gexps once, when user makes first login.  It can
-;;; be used to start user's Shepherd and maybe some other process.  It relies on
-;;; assumption that /run/user/$UID will be created on login by some login
-;;; manager (elogind for example).
-;;;
-;;; home-activation-service-type provides an @file{activate} guile script, which
-;;; do three main things:
-;;;
-;;; - Sets environment variables to the values declared in
-;;; @file{setup-environment} shell script.  It's necessary, because user can set
-;;; for example XDG_CONFIG_HOME and it should be respected by activation gexp of
-;;; symlink-manager.
-;;;
-;;; - Sets GUIX_NEW_HOME and possibly GUIX_OLD_HOME vars to paths in the store.
-;;; Later those variables can be used by activation gexps, for example by
-;;; symlink-manager or run-on-change services.
-;;;
-;;; - Run all activation gexps provided by other home services.
-;;;
-;;; home-run-on-change-service-type allows to trigger actions during
-;;; activation if file or directory specified by pattern is changed.
-;;;
-;;; Code:
-
 
 (define (home-derivation entries mextensions)
   "Return as a monadic value the derivation of the 'home'
diff --git a/gnu/home/services/fontutils.scm b/gnu/home/services/fontutils.scm
index 083cdd4b569..ee5cfda9938 100644
--- a/gnu/home/services/fontutils.scm
+++ b/gnu/home/services/fontutils.scm
@@ -19,6 +19,15 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Services related to fonts.  home-fontconfig service provides
+;;; fontconfig configuration, which allows fc-* utilities to find
+;;; fonts in Guix Home's profile and regenerates font cache on
+;;; activation.
+;;;
+;;; Code:
+
 (define-module (gnu home services fontutils)
   #:use-module (gnu home services)
   #:use-module (gnu packages fontutils)
@@ -29,15 +38,6 @@
 
   #:export (home-fontconfig-service-type))
 
-;;; Commentary:
-;;;
-;;; Services related to fonts.  home-fontconfig service provides
-;;; fontconfig configuration, which allows fc-* utilities to find
-;;; fonts in Guix Home's profile and regenerates font cache on
-;;; activation.
-;;;
-;;; Code:
-
 (define (write-fontconfig-doctype)
   "Prints fontconfig's DOCTYPE to current-output-port."
   ;; This is necessary because SXML doesn't seem to have a way to represent a doctype,
diff --git a/gnu/home/services/mcron.scm b/gnu/home/services/mcron.scm
index eab6b9bda44..2e012ddeb41 100644
--- a/gnu/home/services/mcron.scm
+++ b/gnu/home/services/mcron.scm
@@ -19,13 +19,6 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
-(define-module (gnu home services mcron)
-  #:use-module (gnu home services)
-  #:use-module (gnu home services shepherd)
-  #:use-module (gnu services mcron)               ;for the service mapping
-  #:export (home-mcron-configuration
-            home-mcron-service-type))
-
 ;;; Commentary:
 ;;
 ;; Service for the GNU mcron cron job manager.
@@ -49,6 +42,13 @@
 ;;
 ;;; Code:
 
+(define-module (gnu home services mcron)
+  #:use-module (gnu home services)
+  #:use-module (gnu home services shepherd)
+  #:use-module (gnu services mcron)     ;for the service mapping
+  #:export (home-mcron-configuration
+            home-mcron-service-type))
+
 (define-syntax-rule (home-mcron-configuration fields ...)
   ;; Macro provided for backward compatibility.
   (for-home (mcron-configuration fields ...)))
diff --git a/gnu/home/services/music.scm b/gnu/home/services/music.scm
index 3813ea230e4..86ec82fb359 100644
--- a/gnu/home/services/music.scm
+++ b/gnu/home/services/music.scm
@@ -16,6 +16,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; A Guix Home service to configure Beets, a music file and metadata manager.
+;;;
+;;; Code:
+
 (define-module (gnu home services music)
   #:use-module (guix gexp)
   #:use-module (guix records)
@@ -25,12 +31,6 @@
   #:export (home-beets-configuration
             home-beets-service-type))
 
-;;; Commentary:
-;;;
-;;; A Guix Home service to configure Beets, a music file and metadata manager.
-;;;
-;;; Code:
-
 (define-record-type* <home-beets-configuration>
   home-beets-configuration make-home-beets-configuration
   home-beets-configuration?
diff --git a/gnu/home/services/shells.scm b/gnu/home/services/shells.scm
index b4299957b01..242a2980bda 100644
--- a/gnu/home/services/shells.scm
+++ b/gnu/home/services/shells.scm
@@ -19,6 +19,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module contains shell related services like Zsh.
+;;;
+;;; Code:
+
 (define-module (gnu home services shells)
   #:use-module (gnu services configuration)
   #:use-module ((gnu services) #:select (%default-bash-aliases))
@@ -52,12 +58,6 @@
             home-inputrc-service-type
             home-inputrc-configuration))
 
-;;; Commentary:
-;;;
-;;; This module contains shell related services like Zsh.
-;;;
-;;; Code:
-
 
 ;;;
 ;;; Shell profile.
diff --git a/gnu/home/services/symlink-manager.scm b/gnu/home/services/symlink-manager.scm
index 9f46f07e860..d11d3cdfe6f 100644
--- a/gnu/home/services/symlink-manager.scm
+++ b/gnu/home/services/symlink-manager.scm
@@ -19,13 +19,7 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
-(define-module (gnu home services symlink-manager)
-  #:use-module (gnu home services)
-  #:use-module (guix gexp)
-  #:use-module (guix modules)
-  #:export (home-symlink-manager-service-type))
-
-;;; Comment:
+;;; Commentary:
 ;;;
 ;;; symlink-manager cares about xdg configurations and other files: it backs
 ;;; up files created by user, removes symlinks and directories created by a
@@ -35,6 +29,13 @@
 ;;;
 ;;; Code:
 
+(define-module (gnu home services symlink-manager)
+  #:use-module (gnu home services)
+  #:use-module (guix gexp)
+  #:use-module (guix modules)
+  #:export (home-symlink-manager-service-type))
+
+
 (define (update-symlinks-script)
   (program-file
    "update-symlinks"
diff --git a/gnu/home/services/xdg.scm b/gnu/home/services/xdg.scm
index 04bf2ed4184..6342bb47297 100644
--- a/gnu/home/services/xdg.scm
+++ b/gnu/home/services/xdg.scm
@@ -19,6 +19,17 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;
+;; This module contains services related to XDG directories and
+;; applications.
+;;
+;; - XDG base directories
+;; - XDG user directories
+;; - XDG MIME applications
+;;
+;;; Code:
+
 (define-module (gnu home services xdg)
   #:use-module (gnu services configuration)
   #:use-module (gnu home services)
@@ -62,17 +73,6 @@
             home-xdg-mime-applications-service-type
             home-xdg-mime-applications-configuration))
 
-;;; Commentary:
-;;
-;; This module contains services related to XDG directories and
-;; applications.
-;;
-;; - XDG base directories
-;; - XDG user directories
-;; - XDG MIME applications
-;;
-;;; Code:
-
 
 ;;;
 ;;; XDG base directories.
diff --git a/gnu/installer/connman.scm b/gnu/installer/connman.scm
index d21272036f7..f1d631517f2 100644
--- a/gnu/installer/connman.scm
+++ b/gnu/installer/connman.scm
@@ -16,6 +16,14 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provides procedures for talking with the connman daemon.
+;;; The best approach would have been using connman dbus interface.
+;;; However, as Guile dbus bindings are not available yet, the console client
+;;; "connmanctl" is used to talk with the daemon.
+;;;
+
 (define-module (gnu installer connman)
   #:use-module (gnu installer utils)
   #:use-module (guix records)
@@ -70,14 +78,6 @@
             connman-online?
             connman-connect-with-auth))
 
-;;; Commentary:
-;;;
-;;; This module provides procedures for talking with the connman daemon.
-;;; The best approach would have been using connman dbus interface.
-;;; However, as Guile dbus bindings are not available yet, the console client
-;;; "connmanctl" is used to talk with the daemon.
-;;;
-
 
 ;;;
 ;;; Technology record.
diff --git a/gnu/installer/newt/page.scm b/gnu/installer/newt/page.scm
index c4414fc97ab..e798f4dbcfa 100644
--- a/gnu/installer/newt/page.scm
+++ b/gnu/installer/newt/page.scm
@@ -19,6 +19,17 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Some helpers around guile-newt to draw or run generic pages. The
+;;; difference between 'draw' and 'run' terms comes from newt library. A page
+;;; is drawn when the form it contains does not expect any user
+;;; interaction. In that case, it is necessary to call (newt-refresh) to force
+;;; the page to be displayed. When a form is 'run', it is blocked waiting for
+;;; any action from the user (press a button, input some text, ...).
+;;;
+;;; Code:
+
 (define-module (gnu installer newt page)
   #:use-module (gnu installer steps)
   #:use-module (gnu installer utils)
@@ -52,17 +63,6 @@
 
             run-form-with-clients))
 
-;;; Commentary:
-;;;
-;;; Some helpers around guile-newt to draw or run generic pages. The
-;;; difference between 'draw' and 'run' terms comes from newt library. A page
-;;; is drawn when the form it contains does not expect any user
-;;; interaction. In that case, it is necessary to call (newt-refresh) to force
-;;; the page to be displayed. When a form is 'run', it is blocked waiting for
-;;; any action from the user (press a button, input some text, ...).
-;;;
-;;; Code:
-
 (define* (watch-clients! form #:optional (clients (current-clients)))
   "Have FORM watch the file descriptors corresponding to current client
 connections.  Consequently, FORM may exit with the 'exit-fd-ready' reason."
diff --git a/gnu/installer/tests.scm b/gnu/installer/tests.scm
index a9a5d5d9880..b315176ff4c 100644
--- a/gnu/installer/tests.scm
+++ b/gnu/installer/tests.scm
@@ -18,6 +18,17 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provides tools to test the guided "graphical" installer in a
+;;; non-interactive fashion.  The core of it is 'converse': it allows you to
+;;; state Expect-style dialogues, which happen over the Unix-domain socket the
+;;; installer listens to.  Higher-level procedures such as
+;;; 'choose-locale+keyboard' are provided to perform specific parts of the
+;;; dialogue.
+;;;
+;;; Code:
+
 (define-module (gnu installer tests)
   #:use-module (srfi srfi-1)
   #:use-module (srfi srfi-34)
@@ -44,17 +55,6 @@
 
             edit-configuration-file))
 
-;;; Commentary:
-;;;
-;;; This module provides tools to test the guided "graphical" installer in a
-;;; non-interactive fashion.  The core of it is 'converse': it allows you to
-;;; state Expect-style dialogues, which happen over the Unix-domain socket the
-;;; installer listens to.  Higher-level procedures such as
-;;; 'choose-locale+keyboard' are provided to perform specific parts of the
-;;; dialogue.
-;;;
-;;; Code:
-
 (define %installer-socket-file
   ;; Socket the installer listens to.
   "/var/guix/installer-socket")
diff --git a/gnu/machine.scm b/gnu/machine.scm
index 60be6749727..def1aacb55b 100644
--- a/gnu/machine.scm
+++ b/gnu/machine.scm
@@ -17,6 +17,15 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provides the types used to declare individual machines in a
+;;; heterogeneous Guix deployment. The interface allows users to specify system
+;;; configurations and the means by which resources should be provisioned on a
+;;; per-host basis.
+;;;
+;;; Code:
+
 (define-module (gnu machine)
   #:use-module (gnu system)
   #:use-module (guix derivations)
@@ -48,15 +57,6 @@
             deploy-error-should-roll-back
             deploy-error-captured-args))
 
-;;; Commentary:
-;;;
-;;; This module provides the types used to declare individual machines in a
-;;; heterogeneous Guix deployment. The interface allows users to specify system
-;;; configurations and the means by which resources should be provisioned on a
-;;; per-host basis.
-;;;
-;;; Code:
-
 
 ;;;
 ;;; Declarations for resources that can be provisioned.
diff --git a/gnu/machine/digital-ocean.scm b/gnu/machine/digital-ocean.scm
index d0f0bbe4cb6..f88d140900c 100644
--- a/gnu/machine/digital-ocean.scm
+++ b/gnu/machine/digital-ocean.scm
@@ -19,6 +19,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module implements a high-level interface for provisioning "droplets"
+;;; from the Digital Ocean virtual private server (VPS) service.
+;;;
+;;; Code:
+
 (define-module (gnu machine digital-ocean)
   #:use-module (gnu machine ssh)
   #:use-module (gnu machine)
@@ -63,13 +70,6 @@
 
             digital-ocean-environment-type))
 
-;;; Commentary:
-;;;
-;;; This module implements a high-level interface for provisioning "droplets"
-;;; from the Digital Ocean virtual private server (VPS) service.
-;;;
-;;; Code:
-
 (define %api-base "https://api.digitalocean.com")
 
 (define %digital-ocean-token
diff --git a/gnu/machine/hetzner.scm b/gnu/machine/hetzner.scm
index b4858fa3d26..148e3139b19 100644
--- a/gnu/machine/hetzner.scm
+++ b/gnu/machine/hetzner.scm
@@ -19,6 +19,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module implements a high-level interface for provisioning machines on
+;;; the Hetzner Cloud service https://docs.hetzner.cloud.
+;;;
+
 (define-module (gnu machine hetzner)
   #:use-module (gnu bootloader grub)
   #:use-module (gnu bootloader)
@@ -91,12 +97,6 @@
             hetzner-configuration?
             hetzner-environment-type))
 
-;;; Commentary:
-;;;
-;;; This module implements a high-level interface for provisioning machines on
-;;; the Hetzner Cloud service https://docs.hetzner.cloud.
-;;;
-
 
 ;;;
 ;;; Hetzner operating systems.
diff --git a/gnu/machine/hetzner/http.scm b/gnu/machine/hetzner/http.scm
index f8580021a9e..6702a755351 100644
--- a/gnu/machine/hetzner/http.scm
+++ b/gnu/machine/hetzner/http.scm
@@ -17,6 +17,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module implements a lower-level interface for interacting with the
+;;; Hetzner Cloud API https://docs.hetzner.cloud.
+;;;
+
 (define-module (gnu machine hetzner http)
   #:use-module (guix diagnostics)
   #:use-module (guix i18n)
@@ -179,12 +185,6 @@
             make-hetzner-server-type
             make-hetzner-ssh-key))
 
-;;; Commentary:
-;;;
-;;; This module implements a lower-level interface for interacting with the
-;;; Hetzner Cloud API https://docs.hetzner.cloud.
-;;;
-
 (define %hetzner-default-api-token
   (make-parameter (getenv "GUIX_HETZNER_API_TOKEN")))
 
diff --git a/gnu/machine/ssh.scm b/gnu/machine/ssh.scm
index 0ce28602363..d8c634000f7 100644
--- a/gnu/machine/ssh.scm
+++ b/gnu/machine/ssh.scm
@@ -19,6 +19,15 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module implements remote evaluation and system deployment for
+;;; machines that are accessible over SSH and have a known host-name. In the
+;;; sense of the broader "machine" interface, we describe the environment for
+;;; such machines as 'managed-host.
+;;;
+;;; Code:
+
 (define-module (gnu machine ssh)
   #:use-module (gnu bootloader)
   #:use-module (gnu machine)
@@ -70,15 +79,6 @@
             machine-ssh-configuration-host-key
             machine-ssh-configuration-session))
 
-;;; Commentary:
-;;;
-;;; This module implements remote evaluation and system deployment for
-;;; machines that are accessible over SSH and have a known host-name. In the
-;;; sense of the broader "machine" interface, we describe the environment for
-;;; such machines as 'managed-host.
-;;;
-;;; Code:
-
 
 ;;;
 ;;; Parameters for the SSH client.
diff --git a/gnu/packages.scm b/gnu/packages.scm
index 8d40e3e3352..b0283cade61 100644
--- a/gnu/packages.scm
+++ b/gnu/packages.scm
@@ -21,6 +21,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; General utilities for the software distribution---i.e., the modules under
+;;; (gnu packages ...).
+;;;
+;;; Code:
+
 (define-module (gnu packages)
   #:use-module (guix packages)
   #:use-module (guix ui)
@@ -74,13 +81,6 @@
 
             generate-package-cache))
 
-;;; Commentary:
-;;;
-;;; General utilities for the software distribution---i.e., the modules under
-;;; (gnu packages ...).
-;;;
-;;; Code:
-
 ;; By default, we store patches and auxiliary files
 ;; alongside Guile modules.  This is so that these extra files can be
 ;; found without requiring a special setup, such as a specific
diff --git a/gnu/packages/avr.scm b/gnu/packages/avr.scm
index c445f3a83af..2c8c9486d1b 100644
--- a/gnu/packages/avr.scm
+++ b/gnu/packages/avr.scm
@@ -21,6 +21,17 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module defines a procedure that can be used to create a complete
+;;; avr-toolchain package.  The procedure must not be used at the top level,
+;;; to avoid cyclic module dependencies caused by the (gnu packages
+;;; cross-base) module referring to top level bindings from (gnu packages
+;;; gcc).
+;;;
+;;; It also contains packages for working with or targeting the AVR system.
+;;;
+
 (define-module (gnu packages avr)
   #:use-module ((guix licenses) #:prefix license:)
   #:use-module (guix gexp)
@@ -36,17 +47,6 @@
   #:export (make-avr-libc
             make-avr-toolchain))
 
-;;; Commentary:
-;;;
-;;; This module defines a procedure that can be used to create a complete
-;;; avr-toolchain package.  The procedure must not be used at the top level,
-;;; to avoid cyclic module dependencies caused by the (gnu packages
-;;; cross-base) module referring to top level bindings from (gnu packages
-;;; gcc).
-;;;
-;;; It also contains packages for working with or targeting the AVR system.
-;;;
-
 (define make-avr-binutils
   (mlambda ()
     (package
diff --git a/gnu/packages/base.scm b/gnu/packages/base.scm
index e7d0d2e406c..6fa024b2168 100644
--- a/gnu/packages/base.scm
+++ b/gnu/packages/base.scm
@@ -40,6 +40,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Base packages of the Guix-based GNU user-land software distribution.
+;;;
+;;; Code:
+
 (define-module (gnu packages base)
   #:use-module ((guix licenses)
                 #:select (gpl3+ lgpl2.0+ lgpl3+ public-domain))
@@ -90,12 +96,6 @@
             canonical-package
             %final-inputs))
 
-;;; Commentary:
-;;;
-;;; Base packages of the Guix-based GNU user-land software distribution.
-;;;
-;;; Code:
-
 (define-public hello
   (package
     (name "hello")
diff --git a/gnu/packages/bootstrap.scm b/gnu/packages/bootstrap.scm
index 5555098973c..2fc70210635 100644
--- a/gnu/packages/bootstrap.scm
+++ b/gnu/packages/bootstrap.scm
@@ -23,6 +23,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Pre-built packages that are used to bootstrap the
+;;; distribution--i.e., to build all the core packages from scratch.
+;;;
+;;; Code:
+
 (define-module (gnu packages bootstrap)
   #:use-module (guix licenses)
   #:use-module (gnu packages)
@@ -64,14 +71,6 @@
 
             %bootstrap-inputs-for-tests))
 
-;;; Commentary:
-;;;
-;;; Pre-built packages that are used to bootstrap the
-;;; distribution--i.e., to build all the core packages from scratch.
-;;;
-;;; Code:
-
-
 
 ;;;
 ;;; The bootstrap executables: 'bash', 'mkdir', 'tar', 'xz'.  They allow us to
diff --git a/gnu/packages/commencement.scm b/gnu/packages/commencement.scm
index 8ebcb405975..990930a0073 100644
--- a/gnu/packages/commencement.scm
+++ b/gnu/packages/commencement.scm
@@ -32,6 +32,28 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This is the commencement, this is where things start.  Before the
+;;; commencement, of course, there's the 'bootstrap' module, which provides us
+;;; with the initial binaries.  This module uses those bootstrap binaries to
+;;; actually build up the whole tool chain that make up the implicit inputs of
+;;; 'gnu-build-system'.
+;;;
+;;; To avoid circular dependencies, this module should not be imported
+;;; directly from anywhere.
+;;;
+;;; Below, we frequently use "inherit" to create modified packages.  The
+;;; reason why we use "inherit" instead of "package/inherit" is because we do
+;;; not want these commencement packages to inherit grafts.  By definition,
+;;; these packages are not depended on at run time by any of the packages we
+;;; use.  Thus it does not make sense to inherit grafts.  Furthermore, those
+;;; grafts would often lead to extra overhead for users who would end up
+;;; downloading those "-boot0" packages just to build package replacements
+;;; that are in fact not going to be used.
+;;;
+;;; Code:
+
 (define-module (gnu packages commencement)
   #:use-module (gnu packages)
   #:use-module (gnu packages bootstrap)
@@ -76,28 +98,6 @@
   #:use-module (ice-9 vlist)
   #:use-module (ice-9 match))
 
-;;; Commentary:
-;;;
-;;; This is the commencement, this is where things start.  Before the
-;;; commencement, of course, there's the 'bootstrap' module, which provides us
-;;; with the initial binaries.  This module uses those bootstrap binaries to
-;;; actually build up the whole tool chain that make up the implicit inputs of
-;;; 'gnu-build-system'.
-;;;
-;;; To avoid circular dependencies, this module should not be imported
-;;; directly from anywhere.
-;;;
-;;; Below, we frequently use "inherit" to create modified packages.  The
-;;; reason why we use "inherit" instead of "package/inherit" is because we do
-;;; not want these commencement packages to inherit grafts.  By definition,
-;;; these packages are not depended on at run time by any of the packages we
-;;; use.  Thus it does not make sense to inherit grafts.  Furthermore, those
-;;; grafts would often lead to extra overhead for users who would end up
-;;; downloading those "-boot0" packages just to build package replacements
-;;; that are in fact not going to be used.
-;;;
-;;; Code:
-
 (define built-in-builders*
   (store-lift built-in-builders))
 
diff --git a/gnu/packages/cross-toolchain.scm b/gnu/packages/cross-toolchain.scm
index 733f7e601fe..9f3ecd87af0 100644
--- a/gnu/packages/cross-toolchain.scm
+++ b/gnu/packages/cross-toolchain.scm
@@ -16,11 +16,6 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
-(define-module (gnu packages cross-toolchain)
-  #:use-module (gnu packages cross-base)
-  #:use-module (gnu packages gcc)
-  #:use-module (guix packages))
-
 ;;; Commentary:
 ;;;
 ;;; This module provides packages for cross compilation toolchains.  These
@@ -33,6 +28,11 @@
 ;;; compilation methods. For example, by using the `#:target' argument on
 ;;; packages or `--target' on the command line.
 
+(define-module (gnu packages cross-toolchain)
+  #:use-module (gnu packages cross-base)
+  #:use-module (gnu packages gcc)
+  #:use-module (guix packages))
+
 (define-public gcc-cross-avr-toolchain
   (cross-gcc-toolchain "avr"))
 
diff --git a/gnu/packages/dbm.scm b/gnu/packages/dbm.scm
index e203d22e1ca..21af128411f 100644
--- a/gnu/packages/dbm.scm
+++ b/gnu/packages/dbm.scm
@@ -26,6 +26,11 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module has been separated from (gnu packages databases) to reduce the
+;;; number of module references for core packages.
+
 (define-module (gnu packages dbm)
   #:use-module (gnu packages)
   #:use-module (gnu packages autotools)
@@ -37,11 +42,6 @@
   #:use-module (guix utils)
   #:use-module (ice-9 match))
 
-;;; Commentary:
-;;;
-;;; This module has been separated from (gnu packages databases) to reduce the
-;;; number of module references for core packages.
-
 (define bdb-snippet
   ;; Remove some bundled and generated files.  Some of the old
   ;; Autotools files are too old for some architectures
diff --git a/gnu/packages/duckdb.scm b/gnu/packages/duckdb.scm
index 4a3edf99f21..50da727239b 100644
--- a/gnu/packages/duckdb.scm
+++ b/gnu/packages/duckdb.scm
@@ -21,6 +21,14 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module contains DuckDB - an analytical in-process SQL database
+;;; management system (https://www.duckdb.org/) and it's binding in different
+;;; programming languages with other related to DuckDB packages.
+;;;
+;;; Code:
+
 (define-module (gnu packages duckdb)
   #:use-module ((guix licenses) #:prefix license:)
   #:use-module (guix build-system cmake)
@@ -43,13 +51,6 @@
   #:use-module (gnu packages statistics)
   #:use-module (gnu packages time))
 
-;;; Commentary:
-;;;
-;;; This module contains DuckDB - an analytical in-process SQL database
-;;; management system (https://www.duckdb.org/) and it's binding in different
-;;; programming languages with other related to DuckDB packages.
-;;;
-;;; Code:
 
 (define %duckdb-version "1.5.3")
 
diff --git a/gnu/packages/embedded.scm b/gnu/packages/embedded.scm
index d163ac5a57f..43bb77ae022 100644
--- a/gnu/packages/embedded.scm
+++ b/gnu/packages/embedded.scm
@@ -32,6 +32,15 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This modules contains toolchain generators as well as packages for use in
+;;; embedded contexts.  Note: the toolchain and specialized packages are
+;;; procedures, so as to delay their references to top level bindings such as
+;;; 'gcc' or 'cross-gcc', etc.
+;;;
+;;; Code:
+
 (define-module (gnu packages embedded)
   #:use-module (guix utils)
   #:use-module (guix packages)
@@ -121,14 +130,6 @@
             make-propeller-gcc-6
             make-propeller-toolchain))
 
-;;; Commentary:
-;;;
-;;; This modules contains toolchain generators as well as packages for use in
-;;; embedded contexts.  Note: the toolchain and specialized packages are
-;;; procedures, so as to delay their references to top level bindings such as
-;;; 'gcc' or 'cross-gcc', etc.
-;;;
-
 ;; We must not use the released GCC sources here, because the cross-compiler
 ;; does not produce working binaries.  Instead we take the very same SVN
 ;; revision from the branch that is used for a release of the "GCC ARM
diff --git a/gnu/packages/gnome-circle.scm b/gnu/packages/gnome-circle.scm
index 04f195180b5..1e294f55a24 100644
--- a/gnu/packages/gnome-circle.scm
+++ b/gnu/packages/gnome-circle.scm
@@ -25,7 +25,7 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
-;;; Comment:
+;;; Commentary:
 
 ;;; This module is for packages that are part of GNOME Circle
 ;;; <https://circle.gnome.org/>.
diff --git a/gnu/packages/golang-apps.scm b/gnu/packages/golang-apps.scm
index 9b856d23b5b..80ad63d8535 100644
--- a/gnu/packages/golang-apps.scm
+++ b/gnu/packages/golang-apps.scm
@@ -21,6 +21,18 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Golang (Go) specific applications which are not inherited from their
+;;; source live here e.g linters, language servers, REPL implementations etc.
+;;;
+;;; If the <cmd/APP> is inherited from its source place it in corresponded
+;;; golang-*.scm file in the end after the section "Executables".
+;;;
+;;; Please: Try to add new variable in alphabetical order.
+;;;
+;;; Code:
+
 (define-module (gnu packages golang-apps)
   #:use-module (guix build-system go)
   #:use-module (guix gexp)
@@ -34,17 +46,6 @@
   #:use-module (gnu packages golang-web)
   #:use-module (gnu packages golang-xyz))
 
-;;; Commentary:
-;;;
-;;; Golang (Go) specific applications which are not inherited from their
-;;; source live here e.g linters, language servers, REPL implementations etc.
-;;;
-;;; If the <cmd/APP> is inherited from its source place it in corresponded
-;;; golang-*.scm file in the end after the section "Executables".
-;;;
-;;; Please: Try to add new variable in alphabetical order.
-;;;
-;;; Code:
 
 (define-public go-chroma
   (package
diff --git a/gnu/packages/golang-build.scm b/gnu/packages/golang-build.scm
index 9e744c50c3a..70d99a41a77 100644
--- a/gnu/packages/golang-build.scm
+++ b/gnu/packages/golang-build.scm
@@ -37,18 +37,6 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
-(define-module (gnu packages golang-build)
-  #:use-module ((guix licenses) #:prefix license:)
-  #:use-module (guix build-system go)
-  #:use-module (guix gexp)
-  #:use-module (guix git-download)
-  #:use-module (guix packages)
-  #:use-module (guix utils)
-  #:use-module (gnu packages)
-  #:use-module (gnu packages audio)
-  #:use-module (gnu packages gl)
-  #:use-module (gnu packages golang))
-
 ;;; Commentary:
 ;;;
 ;;; Modules (libraries) which are part of the Golang project but outside the
@@ -61,6 +49,19 @@
 ;;; Please: Try to add new module packages in alphabetic order.
 ;;;
 ;;; Code:
+
+(define-module (gnu packages golang-build)
+  #:use-module ((guix licenses) #:prefix license:)
+  #:use-module (guix build-system go)
+  #:use-module (guix gexp)
+  #:use-module (guix git-download)
+  #:use-module (guix packages)
+  #:use-module (guix utils)
+  #:use-module (gnu packages)
+  #:use-module (gnu packages audio)
+  #:use-module (gnu packages gl)
+  #:use-module (gnu packages golang))
+
 
 (define-public go-cel-dev-expr
   (package
diff --git a/gnu/packages/golang-check.scm b/gnu/packages/golang-check.scm
index b3ef530bf22..d05e0ee2c59 100644
--- a/gnu/packages/golang-check.scm
+++ b/gnu/packages/golang-check.scm
@@ -45,6 +45,16 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Golang packages providing tools to unit-test, mock, assert, and lint
+;;; processes for the Golang itself. They may provide executables and
+;;; libraries, for which there are marked sections.
+;;;
+;;; Please: Try to add new module packages in alphabetic order.
+;;;
+;;; Code:
+
 (define-module (gnu packages golang-check)
   #:use-module ((guix licenses) #:prefix license:)
   #:use-module (guix packages)
@@ -59,15 +69,6 @@
   #:use-module (gnu packages golang-xyz)
   #:use-module (gnu packages version-control))
 
-;;; Commentary:
-;;;
-;;; Golang packages providing tools to unit-test, mock, assert, and lint
-;;; processes for the Golang itself. They may provide executables and
-;;; libraries, for which there are marked sections.
-;;;
-;;; Please: Try to add new module packages in alphabetic order.
-;;;
-;;; Code:
 
 ;;;
 ;;; Libraries:
diff --git a/gnu/packages/golang-compression.scm b/gnu/packages/golang-compression.scm
index 2ea0b01110a..ee406036571 100644
--- a/gnu/packages/golang-compression.scm
+++ b/gnu/packages/golang-compression.scm
@@ -23,6 +23,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Please: Try to add new module packages in alphabetic order.
+;;;
+;;; Code:
+
 (define-module (gnu packages golang-compression)
   #:use-module ((guix licenses) #:prefix license:)
   #:use-module (guix build-system go)
@@ -38,11 +44,6 @@
   #:use-module (gnu packages golang-xyz)
   #:use-module (gnu packages pkg-config))
 
-;;; Commentary:
-;;;
-;;; Please: Try to add new module packages in alphabetic order.
-;;;
-;;; Code:
 
 (define-public go-code-forgejo-org-forgejo-go-rpmutils
   (package
diff --git a/gnu/packages/golang-crypto.scm b/gnu/packages/golang-crypto.scm
index 7e54b4d9818..d197029bfdf 100644
--- a/gnu/packages/golang-crypto.scm
+++ b/gnu/packages/golang-crypto.scm
@@ -48,6 +48,16 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Golang modules (libraries) related to Cryptography: encryption algorithms,
+;;; hashing functions, TLS, key management, digital signatures, password
+;;; hashing etc.
+;;;
+;;; Please: Try to add new module packages in alphabetic order.
+;;;
+;;; Code:
+
 (define-module (gnu packages golang-crypto)
   #:use-module ((guix licenses) #:prefix license:)
   #:use-module (guix build-system go)
@@ -70,15 +80,6 @@
   #:use-module (gnu packages specifications)
   #:use-module (gnu packages tls))
 
-;;; Commentary:
-;;;
-;;; Golang modules (libraries) related to Cryptography: encryption algorithms,
-;;; hashing functions, TLS, key management, digital signatures, password
-;;; hashing etc.
-;;;
-;;; Please: Try to add new module packages in alphabetic order.
-;;;
-;;; Code:
 
 ;;;
 ;;; Libraries:
diff --git a/gnu/packages/golang-graphics.scm b/gnu/packages/golang-graphics.scm
index 725ffad1b77..6dadb0e3746 100644
--- a/gnu/packages/golang-graphics.scm
+++ b/gnu/packages/golang-graphics.scm
@@ -18,6 +18,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Please: Try to add new module packages in alphabetic order.
+;;;
+;;; Code:
+
 (define-module (gnu packages golang-graphics)
   #:use-module (guix build-system go)
   #:use-module (guix gexp)
@@ -33,11 +39,6 @@
   #:use-module (gnu packages pkg-config)
   #:use-module (gnu packages xorg))
 
-;;; Commentary:
-;;;
-;;; Please: Try to add new module packages in alphabetic order.
-;;;
-;;; Code:
 
 ;;;
 ;;; Libraries:
diff --git a/gnu/packages/golang-maths.scm b/gnu/packages/golang-maths.scm
index 71d3e3c6e52..895557a6dbb 100644
--- a/gnu/packages/golang-maths.scm
+++ b/gnu/packages/golang-maths.scm
@@ -20,6 +20,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Please: Try to add new module packages in alphabetic order.
+;;;
+;;; Code:
+
 (define-module (gnu packages golang-maths)
   #:use-module ((guix licenses) #:prefix license:)
   #:use-module (guix build-system go)
@@ -33,11 +39,6 @@
   #:use-module (gnu packages golang-check)
   #:use-module (gnu packages golang-compression))
 
-;;; Commentary:
-;;;
-;;; Please: Try to add new module packages in alphabetic order.
-;;;
-;;; Code:
 
 ;;;
 ;;; Libraries:
diff --git a/gnu/packages/golang-vcs.scm b/gnu/packages/golang-vcs.scm
index d74be58bf26..f1374c8d5dc 100644
--- a/gnu/packages/golang-vcs.scm
+++ b/gnu/packages/golang-vcs.scm
@@ -21,6 +21,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Please: Try to add new module packages in alphabetic order.
+;;;
+;;; Code:
+
 (define-module (gnu packages golang-vcs)
   #:use-module ((guix licenses) #:prefix license:)
   #:use-module (guix build-system go)
@@ -43,11 +49,6 @@
   #:use-module (gnu packages python-check)
   #:use-module (gnu packages version-control))
 
-;;; Commentary:
-;;;
-;;; Please: Try to add new module packages in alphabetic order.
-;;;
-;;; Code:
 
 ;;;
 ;;; Libraries:
diff --git a/gnu/packages/golang-web.scm b/gnu/packages/golang-web.scm
index 320e15dc863..a673448d5cf 100644
--- a/gnu/packages/golang-web.scm
+++ b/gnu/packages/golang-web.scm
@@ -68,6 +68,19 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Golang modules (libraries) for Web related projects: HTML, CSS, SCSS,
+;;; JavaScript, JSON, Web-framework, REST-API or similar functionality; for
+;;; Network related projects: OSI layers implementation algorithms, MIME,
+;;; Email protocols implementations, and similar.  They may provide
+;;; executables and libraries, for which there are marked sections.
+
+;;;
+;;; Please: Try to add new module packages in alphabetic order.
+;;;
+;;; Code:
+
 (define-module (gnu packages golang-web)
   #:use-module ((guix licenses) #:prefix license:)
   #:use-module (guix packages)
@@ -91,18 +104,6 @@
   #:use-module (gnu packages tls)
   #:use-module (gnu packages web))
 
-;;; Commentary:
-;;;
-;;; Golang modules (libraries) for Web related projects: HTML, CSS, SCSS,
-;;; JavaScript, JSON, Web-framework, REST-API or similar functionality; for
-;;; Network related projects: OSI layers implementation algorithms, MIME,
-;;; Email protocols implementations, and similar.  They may provide
-;;; executables and libraries, for which there are marked sections.
-
-;;;
-;;; Please: Try to add new module packages in alphabetic order.
-;;;
-;;; Code:
 
 ;;;
 ;;; Libraries:
diff --git a/gnu/packages/golang-xyz.scm b/gnu/packages/golang-xyz.scm
index d465888f8ac..eca17e73700 100644
--- a/gnu/packages/golang-xyz.scm
+++ b/gnu/packages/golang-xyz.scm
@@ -99,6 +99,20 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Nomad Golang modules (libraries) are welcome here.
+;;;
+;;; There are two sections her: Libraries - for any source only Golang
+;;; libraries which are meant to be imported by other packages; Executables -
+;;; should contain inherited packages where commands need to be built.
+;;;
+;;; Please: Try to add new module packages in alphabetic order and avoid stand
+;;; alone final executables which are not inherited from sources presented in
+;;; this module.
+;;;
+;;; Code:
+
 (define-module (gnu packages golang-xyz)
   #:use-module ((guix licenses) #:prefix license:)
   #:use-module (guix build-system go)
@@ -140,19 +154,6 @@
   #:use-module (gnu packages kubernetes)
   #:use-module (gnu packages prometheus))
 
-;;; Commentary:
-;;;
-;;; Nomad Golang modules (libraries) are welcome here.
-;;;
-;;; There are two sections her: Libraries - for any source only Golang
-;;; libraries which are meant to be imported by other packages; Executables -
-;;; should contain inherited packages where commands need to be built.
-;;;
-;;; Please: Try to add new module packages in alphabetic order and avoid stand
-;;; alone final executables which are not inherited from sources presented in
-;;; this module.
-;;;
-;;; Code:
 
 ;;;
 ;;; Libraries:
diff --git a/gnu/packages/guile.scm b/gnu/packages/guile.scm
index ba46a34bd91..58c1598bb38 100644
--- a/gnu/packages/guile.scm
+++ b/gnu/packages/guile.scm
@@ -34,6 +34,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; GNU Guile, and modules and extensions.
+;;;
+;;; Code:
+
 (define-module (gnu packages guile)
   #:use-module ((guix licenses) #:prefix license:)
   #:use-module (gnu packages)
@@ -67,12 +73,6 @@
   #:use-module (guix deprecation)
   #:use-module (guix utils))
 
-;;; Commentary:
-;;;
-;;; GNU Guile, and modules and extensions.
-;;;
-;;; Code:
-
 (define-public guile-1.8
   (package
    (name "guile")
diff --git a/gnu/packages/ld-wrapper.in b/gnu/packages/ld-wrapper.in
index c9bb235bca5..61d65b262d9 100644
--- a/gnu/packages/ld-wrapper.in
+++ b/gnu/packages/ld-wrapper.in
@@ -39,12 +39,6 @@ exec @GUILE@ -c "(load-compiled \"@SELF@.go\") ($main (command-line))" "$@"
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
-(define-module (gnu build-support ld-wrapper)
-  #:use-module (srfi srfi-1)
-  #:use-module (ice-9 match)
-  #:autoload   (ice-9 rdelim) (read-delimited)
-  #:export (ld-wrapper))
-
 ;;; Commentary:
 ;;;
 ;;; This is a wrapper for the linker.  Its purpose is to inspect the -L and
@@ -70,6 +64,12 @@ exec @GUILE@ -c "(load-compiled \"@SELF@.go\") ($main (command-line))" "$@"
 ;;;
 ;;; Code:
 
+(define-module (gnu build-support ld-wrapper)
+  #:use-module (srfi srfi-1)
+  #:use-module (ice-9 match)
+  #:autoload   (ice-9 rdelim) (read-delimited)
+  #:export (ld-wrapper))
+
 (define %real-ld
   ;; Name of the linker that we wrap.
   "@LD@")
diff --git a/gnu/packages/make-bootstrap.scm b/gnu/packages/make-bootstrap.scm
index de1dd6ebd22..71eedb138ac 100644
--- a/gnu/packages/make-bootstrap.scm
+++ b/gnu/packages/make-bootstrap.scm
@@ -23,6 +23,14 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provides tools to build tarballs of the "bootstrap binaries"
+;;; used in (gnu packages bootstrap).  These statically-linked binaries are
+;;; taken for granted and used as the root of the whole bootstrap procedure.
+;;;
+;;; Code:
+
 (define-module (gnu packages make-bootstrap)
   #:use-module (guix gexp)
   #:use-module (guix utils)
@@ -58,14 +66,6 @@
             %guile-static-stripped
             %guile-static-initrd))
 
-;;; Commentary:
-;;;
-;;; This module provides tools to build tarballs of the "bootstrap binaries"
-;;; used in (gnu packages bootstrap).  These statically-linked binaries are
-;;; taken for granted and used as the root of the whole bootstrap procedure.
-;;;
-;;; Code:
-
 (define glibc-for-bootstrap
   (mlambdaq (base)
     "Return a libc deriving from BASE whose `system' and `popen' functions looks
diff --git a/gnu/packages/prometheus.scm b/gnu/packages/prometheus.scm
index 910ee9e3c9e..1ab3f367217 100644
--- a/gnu/packages/prometheus.scm
+++ b/gnu/packages/prometheus.scm
@@ -24,6 +24,15 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Libraries and commands related to, or provided by Prometheus project
+;;; <https://prometheus.io>.
+;;;
+;;; Please: Try to add new module packages in alphabetic order.
+;;;
+;;; Code:
+
 (define-module (gnu packages prometheus)
   #:use-module ((guix licenses) #:prefix license:)
   #:use-module (guix build-system go)
@@ -40,14 +49,6 @@
   #:use-module (gnu packages golang-web)
   #:use-module (gnu packages golang-xyz))
 
-;;; Commentary:
-;;;
-;;; Libraries and commands related to, or provided by Prometheus project
-;;; <https://prometheus.io>.
-;;;
-;;; Please: Try to add new module packages in alphabetic order.
-;;;
-;;; Code:
 
 ;;;
 ;;; Libraries:
diff --git a/gnu/packages/python-build.scm b/gnu/packages/python-build.scm
index 69da97a8bc4..433bee7bf71 100644
--- a/gnu/packages/python-build.scm
+++ b/gnu/packages/python-build.scm
@@ -38,6 +38,14 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Python packages to build... Python packages.  Since they are bound to be
+;;; relied on by many, their dependencies should be kept minimal, and this
+;;; module should not depend on other modules containing Python packages.
+;;;
+;;; Code:
+
 (define-module (gnu packages python-build)
   #:use-module (gnu packages)
   #:use-module (gnu packages bash)
@@ -50,14 +58,6 @@
   #:use-module (guix git-download)
   #:use-module (guix packages))
 
-;;; Commentary:
-;;;
-;;; Python packages to build... Python packages.  Since they are bound to be
-;;; relied on by many, their dependencies should be kept minimal, and this
-;;; module should not depend on other modules containing Python packages.
-;;;
-;;; Code:
-
 
 ;;; These are dependencies used by the build systems contained herein; they
 ;;; feel a bit out of place but are kept here to prevent circular module
diff --git a/gnu/packages/python-graphics.scm b/gnu/packages/python-graphics.scm
index e7e07302af8..57e35610c21 100644
--- a/gnu/packages/python-graphics.scm
+++ b/gnu/packages/python-graphics.scm
@@ -29,6 +29,15 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Python modules which are meant to be used in GUI creation or mainly are
+;;; bindings to low level libraries such as Glue, Mesa, OpenGL, Xorg etc.
+;;;
+;;; Please: Try to add new module packages in alphabetic order.
+;;;
+;;; Code:
+
 (define-module (gnu packages python-graphics)
   #:use-module ((guix licenses) #:prefix license:)
   #:use-module (guix build-system pyproject)
@@ -68,14 +77,6 @@
   #:use-module (gnu packages video)
   #:use-module (gnu packages xorg))
 
-;;; Commentary:
-;;;
-;;; Python modules which are meant to be used in GUI creation or mainly are
-;;; bindings to low level libraries such as Glue, Mesa, OpenGL, Xorg etc.
-;;;
-;;; Please: Try to add new module packages in alphabetic order.
-;;;
-;;; Code:
 
 (define-public python-asyncgui
   (package
diff --git a/gnu/packages/quantum.scm b/gnu/packages/quantum.scm
index 908a51773a4..5ca1846e353 100644
--- a/gnu/packages/quantum.scm
+++ b/gnu/packages/quantum.scm
@@ -18,6 +18,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Quantum computing and tensor operation module. For quantum mechanics
+;;; select (gnu packages physics) module.
+;;;
+;;; Code:
+
 (define-module (gnu packages quantum)
   #:use-module (gnu packages)
   #:use-module (gnu packages check)
@@ -35,12 +42,6 @@
   #:use-module ((guix licenses) #:prefix license:)
   #:use-module (guix packages))
 
-;;; Commentary:
-;;;
-;;; Quantum computing and tensor operation module. For quantum mechanics
-;;; select (gnu packages physics) module.
-;;;
-;;; Code:
 
 
 (define %cirq-version "1.7.0")
diff --git a/gnu/packages/ruby-check.scm b/gnu/packages/ruby-check.scm
index 6535d8fd6e4..0406cf3fd2e 100644
--- a/gnu/packages/ruby-check.scm
+++ b/gnu/packages/ruby-check.scm
@@ -48,6 +48,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Please: Try to add new module packages in alphabetic order.
+;;;
+;;; Code:
+
 (define-module (gnu packages ruby-check)
   #:use-module ((guix licenses) #:prefix license:)
   #:use-module (guix build-system ruby)
@@ -61,11 +67,6 @@
   #:use-module (gnu packages ruby)
   #:use-module (gnu packages ruby-xyz))
 
-;;; Commentary:
-;;;
-;;; Please: Try to add new module packages in alphabetic order.
-;;;
-;;; Code:
 
 
 ;; Bundler is yet another source of circular dependencies, so we must disable
diff --git a/gnu/packages/sqlite.scm b/gnu/packages/sqlite.scm
index 24a5f741ed3..972e84a6c44 100644
--- a/gnu/packages/sqlite.scm
+++ b/gnu/packages/sqlite.scm
@@ -31,6 +31,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module has been separated from (gnu packages databases) to reduce the
+;;; number of module references for core packages.
+;;;
+;;; Code:
+
 (define-module (gnu packages sqlite)
   #:use-module (gnu packages)
   #:use-module (gnu packages hurd)
@@ -45,11 +52,6 @@
   #:use-module (ice-9 match)
   #:use-module (srfi srfi-26))
 
-;;; Commentary:
-;;;
-;;; This module has been separated from (gnu packages databases) to reduce the
-;;; number of module references for core packages.
-
 (define (sqlite-uri version year)
   (let ((numeric-version
          (match (string-split version #\.)
diff --git a/gnu/packages/tex.scm b/gnu/packages/tex.scm
index b8b55242eb4..6d961151d54 100644
--- a/gnu/packages/tex.scm
+++ b/gnu/packages/tex.scm
@@ -48,76 +48,6 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
-(define-module (gnu packages tex)
-  #:use-module ((guix licenses) #:prefix license:)
-  #:use-module (guix gexp)
-  #:use-module (guix packages)
-  #:use-module (guix download)
-  #:use-module (guix build-system copy)
-  #:use-module (guix build-system gnu)
-  #:use-module (guix build-system perl)
-  #:use-module (guix build-system pyproject)
-  #:use-module (guix build-system qt)
-  #:use-module (guix build-system trivial)
-  #:use-module (guix build-system texlive)
-  #:use-module (guix utils)
-  #:use-module (guix deprecation)
-  #:use-module (guix gexp)
-  #:use-module (guix git-download)
-  #:use-module (guix svn-download)
-  #:use-module (gnu packages)
-  #:use-module (gnu packages algebra)
-  #:use-module (gnu packages aspell)
-  #:use-module (gnu packages autotools)
-  #:use-module (gnu packages bash)
-  #:use-module (gnu packages boost)
-  #:use-module (gnu packages check)
-  #:use-module (gnu packages compression)
-  #:use-module (gnu packages cmake)
-  #:use-module (gnu packages cpp)
-  #:use-module (gnu packages digest)
-  #:use-module (gnu packages lisp)
-  #:use-module (gnu packages fonts)
-  #:use-module (gnu packages fontutils)
-  #:use-module (gnu packages gd)
-  #:use-module (gnu packages ghostscript)
-  #:use-module (gnu packages graphviz)
-  #:use-module (gnu packages groff)
-  #:use-module (gnu packages gtk)
-  #:use-module (gnu packages icu4c)
-  #:use-module (gnu packages image)
-  #:use-module (gnu packages java)
-  #:use-module (gnu packages libreoffice)
-  #:use-module (gnu packages lua)
-  #:use-module (gnu packages maths)
-  #:use-module (gnu packages multiprecision)
-  #:use-module (gnu packages pdf)
-  #:use-module (gnu packages perl)
-  #:use-module (gnu packages perl-check)
-  #:use-module (gnu packages pkg-config)
-  #:use-module (gnu packages plotutils)
-  #:use-module (gnu packages python)
-  #:use-module (gnu packages python-build)
-  #:use-module (gnu packages python-xyz)
-  #:use-module (gnu packages qt)
-  #:use-module (gnu packages readline)
-  #:use-module (gnu packages ruby)
-  #:use-module (gnu packages ruby-xyz)
-  #:use-module (gnu packages shells)
-  #:use-module (gnu packages tcl)
-  #:use-module (gnu packages time)
-  #:use-module (gnu packages tls)
-  #:use-module (gnu packages base)
-  #:use-module (gnu packages gawk)
-  #:use-module (gnu packages web)
-  #:use-module (gnu packages xml)
-  #:use-module (gnu packages xorg)
-  #:use-module (gnu packages xdisorg)
-  #:use-module (gnu packages texinfo)
-  #:use-module (ice-9 ftw)
-  #:use-module (ice-9 match)
-  #:use-module ((srfi srfi-1) #:hide (zip)))
-
 ;;; Commentary:
 ;;;
 ;;; Guix provides two different TeX Live systems: one monolithic, the TEXLIVE
@@ -270,6 +200,76 @@
 ;;;
 ;;; Code:
 
+(define-module (gnu packages tex)
+  #:use-module ((guix licenses) #:prefix license:)
+  #:use-module (guix gexp)
+  #:use-module (guix packages)
+  #:use-module (guix download)
+  #:use-module (guix build-system copy)
+  #:use-module (guix build-system gnu)
+  #:use-module (guix build-system perl)
+  #:use-module (guix build-system pyproject)
+  #:use-module (guix build-system qt)
+  #:use-module (guix build-system trivial)
+  #:use-module (guix build-system texlive)
+  #:use-module (guix utils)
+  #:use-module (guix deprecation)
+  #:use-module (guix gexp)
+  #:use-module (guix git-download)
+  #:use-module (guix svn-download)
+  #:use-module (gnu packages)
+  #:use-module (gnu packages algebra)
+  #:use-module (gnu packages aspell)
+  #:use-module (gnu packages autotools)
+  #:use-module (gnu packages bash)
+  #:use-module (gnu packages boost)
+  #:use-module (gnu packages check)
+  #:use-module (gnu packages compression)
+  #:use-module (gnu packages cmake)
+  #:use-module (gnu packages cpp)
+  #:use-module (gnu packages digest)
+  #:use-module (gnu packages lisp)
+  #:use-module (gnu packages fonts)
+  #:use-module (gnu packages fontutils)
+  #:use-module (gnu packages gd)
+  #:use-module (gnu packages ghostscript)
+  #:use-module (gnu packages graphviz)
+  #:use-module (gnu packages groff)
+  #:use-module (gnu packages gtk)
+  #:use-module (gnu packages icu4c)
+  #:use-module (gnu packages image)
+  #:use-module (gnu packages java)
+  #:use-module (gnu packages libreoffice)
+  #:use-module (gnu packages lua)
+  #:use-module (gnu packages maths)
+  #:use-module (gnu packages multiprecision)
+  #:use-module (gnu packages pdf)
+  #:use-module (gnu packages perl)
+  #:use-module (gnu packages perl-check)
+  #:use-module (gnu packages pkg-config)
+  #:use-module (gnu packages plotutils)
+  #:use-module (gnu packages python)
+  #:use-module (gnu packages python-build)
+  #:use-module (gnu packages python-xyz)
+  #:use-module (gnu packages qt)
+  #:use-module (gnu packages readline)
+  #:use-module (gnu packages ruby)
+  #:use-module (gnu packages ruby-xyz)
+  #:use-module (gnu packages shells)
+  #:use-module (gnu packages tcl)
+  #:use-module (gnu packages time)
+  #:use-module (gnu packages tls)
+  #:use-module (gnu packages base)
+  #:use-module (gnu packages gawk)
+  #:use-module (gnu packages web)
+  #:use-module (gnu packages xml)
+  #:use-module (gnu packages xorg)
+  #:use-module (gnu packages xdisorg)
+  #:use-module (gnu packages texinfo)
+  #:use-module (ice-9 ftw)
+  #:use-module (ice-9 match)
+  #:use-module ((srfi srfi-1) #:hide (zip)))
+
 (define-public texlive-source
   (package
     (name "texlive-source")
diff --git a/gnu/packages/toys.scm b/gnu/packages/toys.scm
index 96824438c17..0c35bd8015c 100644
--- a/gnu/packages/toys.scm
+++ b/gnu/packages/toys.scm
@@ -25,6 +25,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Please: Try to add new module packages in alphabetic order.
+;;;
+;;; Code:
+
 (define-module (gnu packages toys)
   #:use-module ((guix licenses) #:prefix license:)
   #:use-module (guix build-system copy)
@@ -54,11 +60,6 @@
   #:use-module (gnu packages xml)
   #:use-module (gnu packages xorg))
 
-;;; Commentary:
-;;;
-;;; Please: Try to add new module packages in alphabetic order.
-;;;
-;;; Code:
 
 (define-public cbonsai
     (package
diff --git a/gnu/services.scm b/gnu/services.scm
index 097bfed5f1b..5f987f55a52 100644
--- a/gnu/services.scm
+++ b/gnu/services.scm
@@ -26,6 +26,31 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module defines a broad notion of "service types" and "services."
+;;;
+;;; A service type describe how its instances extend instances of other
+;;; service types.  For instance, some services extend the instance of
+;;; ACCOUNT-SERVICE-TYPE by providing it with accounts and groups to create;
+;;; others extend SHEPHERD-ROOT-SERVICE-TYPE by passing it instances of
+;;; <shepherd-service>.
+;;;
+;;; When applicable, the service type defines how it can itself be extended,
+;;; by providing one procedure to compose extensions, and one procedure to
+;;; extend itself.
+;;;
+;;; A notable service type is SYSTEM-SERVICE-TYPE, which has a single
+;;; instance, which is the root of the service DAG.  Its value is the
+;;; derivation that produces the 'system' directory as returned by
+;;; 'operating-system-derivation'.
+;;;
+;;; The 'fold-services' procedure can be passed a list of procedures, which it
+;;; "folds" by propagating extensions down the graph; it returns the root
+;;; service after the applying all its extensions.
+;;;
+;;; Code:
+
 (define-module (gnu services)
   #:use-module (guix derivations)
   #:use-module (guix gexp)
@@ -149,31 +174,6 @@
                ;; <https://debbugs.gnu.org/cgi/bugreport.cgi?bug=26805#16>.
                delete))
 
-;;; Comment:
-;;;
-;;; This module defines a broad notion of "service types" and "services."
-;;;
-;;; A service type describe how its instances extend instances of other
-;;; service types.  For instance, some services extend the instance of
-;;; ACCOUNT-SERVICE-TYPE by providing it with accounts and groups to create;
-;;; others extend SHEPHERD-ROOT-SERVICE-TYPE by passing it instances of
-;;; <shepherd-service>.
-;;;
-;;; When applicable, the service type defines how it can itself be extended,
-;;; by providing one procedure to compose extensions, and one procedure to
-;;; extend itself.
-;;;
-;;; A notable service type is SYSTEM-SERVICE-TYPE, which has a single
-;;; instance, which is the root of the service DAG.  Its value is the
-;;; derivation that produces the 'system' directory as returned by
-;;; 'operating-system-derivation'.
-;;;
-;;; The 'fold-services' procedure can be passed a list of procedures, which it
-;;; "folds" by propagating extensions down the graph; it returns the root
-;;; service after the applying all its extensions.
-;;;
-;;; Code:
-
 (define-record-type <service-extension>
   (service-extension target compute)
   service-extension?
diff --git a/gnu/services/admin.scm b/gnu/services/admin.scm
index 907f7d37f4a..bad9d38e369 100644
--- a/gnu/services/admin.scm
+++ b/gnu/services/admin.scm
@@ -21,6 +21,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provides basic system administration tools: log rotation,
+;;; unattended upgrades, etc.
+;;;
+;;; Code:
+
 (define-module (gnu services admin)
   #:use-module (gnu system file-systems)
   #:use-module (gnu packages admin)
@@ -102,13 +109,6 @@
             resize-file-system-configuration-btrfs-progs
             resize-file-system-configuration-bcachefs-tools))
 
-;;; Commentary:
-;;;
-;;; This module provides basic system administration tools: log rotation,
-;;; unattended upgrades, etc.
-;;;
-;;; Code:
-
 
 ;;;
 ;;; Shepherd's log rotation service.
diff --git a/gnu/services/audio.scm b/gnu/services/audio.scm
index 2981b89ed8c..2e17c02513b 100644
--- a/gnu/services/audio.scm
+++ b/gnu/services/audio.scm
@@ -19,6 +19,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Audio related services
+;;;
+;;; Code:
+
 (define-module (gnu services audio)
   #:use-module (guix gexp)
   #:use-module (guix deprecation)
@@ -163,12 +169,6 @@
             snapserver-configuration-extra-content
             snapserver-service-type))
 
-;;; Commentary:
-;;;
-;;; Audio related services
-;;;
-;;; Code:
-
 (define (uglify-field-name field-name)
   (let ((str (symbol->string field-name)))
     (string-join (string-split (if (string-suffix? "?" str)
diff --git a/gnu/services/avahi.scm b/gnu/services/avahi.scm
index d0e6fedf59d..77d6f950b9f 100644
--- a/gnu/services/avahi.scm
+++ b/gnu/services/avahi.scm
@@ -16,6 +16,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provides service definitions for the Avahi
+;;; "zero-configuration" tool set.
+;;;
+;;; Code:
+
 (define-module (gnu services avahi)
   #:use-module (gnu services)
   #:use-module (gnu services base)
@@ -42,13 +49,6 @@
 
             avahi-service-type))
 
-;;; Commentary:
-;;;
-;;; This module provides service definitions for the Avahi
-;;; "zero-configuration" tool set.
-;;;
-;;; Code:
-
 (define-record-type* <avahi-configuration>
   avahi-configuration make-avahi-configuration
   avahi-configuration?
diff --git a/gnu/services/base.scm b/gnu/services/base.scm
index 5108187d1ee..4bfc484b898 100644
--- a/gnu/services/base.scm
+++ b/gnu/services/base.scm
@@ -40,6 +40,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Base system services---i.e., services that 99% of the users will want to
+;;; use.
+;;;
+;;; Code:
+
 (define-module (gnu services base)
   #:use-module (guix store)
   #:use-module (guix deprecation)
@@ -321,13 +328,6 @@
 
             %base-services))
 
-;;; Commentary:
-;;;
-;;; Base system services---i.e., services that 99% of the users will want to
-;;; use.
-;;;
-;;; Code:
-
 
 
 ;;;
diff --git a/gnu/services/certbot.scm b/gnu/services/certbot.scm
index 7a7c2a9e00e..f1ab9149f6a 100644
--- a/gnu/services/certbot.scm
+++ b/gnu/services/certbot.scm
@@ -24,6 +24,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Automatically obtaining TLS certificates from Let's Encrypt.
+;;;
+;;; Code:
+
 (define-module (gnu services certbot)
   #:use-module (gnu services)
   #:use-module (gnu services base)
@@ -42,12 +48,6 @@
             certbot-configuration?
             certificate-configuration))
 
-;;; Commentary:
-;;;
-;;; Automatically obtaining TLS certificates from Let's Encrypt.
-;;;
-;;; Code:
-
 
 (define-record-type* <certificate-configuration>
   certificate-configuration make-certificate-configuration
diff --git a/gnu/services/cgit.scm b/gnu/services/cgit.scm
index 684ab73f76d..f2d1be04f05 100644
--- a/gnu/services/cgit.scm
+++ b/gnu/services/cgit.scm
@@ -19,6 +19,16 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provides a service definition for the Cgit a web frontend for
+;;; Git repositories written in C.
+;;;
+;;; Note: fields of <cgit-configuration> and <repository-cgit-configuration>
+;;; should be specified in the specific order.
+;;;
+;;; Code:
+
 (define-module (gnu services cgit)
   #:use-module (gnu packages admin)
   #:use-module (gnu packages version-control)
@@ -42,16 +52,6 @@
             opaque-cgit-configuration
             cgit-service-type))
 
-;;; Commentary:
-;;;
-;;; This module provides a service definition for the Cgit a web frontend for
-;;; Git repositories written in C.
-;;;
-;;; Note: fields of <cgit-configuration> and <repository-cgit-configuration>
-;;; should be specified in the specific order.
-;;;
-;;; Code:
-
 (define %cgit-configuration-nginx
   (nginx-server-configuration
    (root cgit)
diff --git a/gnu/services/ci.scm b/gnu/services/ci.scm
index 08416e99620..61c0166eed2 100644
--- a/gnu/services/ci.scm
+++ b/gnu/services/ci.scm
@@ -19,6 +19,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;;; Commentary:
+;;;
+;;; This module implements a service that to run instances of Laminar, a
+;;; continuous integration tool.
+;;;
+;;;; Code:
+
 (define-module (gnu services ci)
   #:use-module (guix gexp)
   #:use-module (guix records)
@@ -59,13 +66,6 @@
 
             forgejo-runner-service-type))
 
-;;;; Commentary:
-;;;
-;;; This module implements a service that to run instances of Laminar, a
-;;; continuous integration tool.
-;;;
-;;;; Code:
-
 (define-record-type* <laminar-configuration>
   laminar-configuration make-laminar-configuration
   laminar-configuration?
diff --git a/gnu/services/configuration.scm b/gnu/services/configuration.scm
index d42f04f1161..956f4451fd1 100644
--- a/gnu/services/configuration.scm
+++ b/gnu/services/configuration.scm
@@ -24,6 +24,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Syntax for creating Scheme bindings to complex configuration files.
+;;;
+;;; Code:
+
 (define-module (gnu services configuration)
   #:use-module (guix packages)
   #:use-module (guix records)
@@ -92,12 +98,6 @@
             generic-serialize-alist-entry
             generic-serialize-alist))
 
-;;; Commentary:
-;;;
-;;; Syntax for creating Scheme bindings to complex configuration files.
-;;;
-;;; Code:
-
 (define-condition-type &configuration-error &error
   configuration-error?)
 
diff --git a/gnu/services/cuirass.scm b/gnu/services/cuirass.scm
index b594fe78d7a..77d7cab96ce 100644
--- a/gnu/services/cuirass.scm
+++ b/gnu/services/cuirass.scm
@@ -21,6 +21,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;;; Commentary:
+;;;
+;;; This module implements a service that to run instances of Cuirass, a
+;;; continuous integration tool.
+;;;
+;;;; Code:
+
 (define-module (gnu services cuirass)
   #:use-module (guix channels)
   #:use-module (guix gexp)
@@ -50,13 +57,6 @@
             cuirass-remote-worker-configuration?
             cuirass-remote-worker-service-type))
 
-;;;; Commentary:
-;;;
-;;; This module implements a service that to run instances of Cuirass, a
-;;; continuous integration tool.
-;;;
-;;;; Code:
-
 (define %cuirass-default-database
   "dbname=cuirass")
 
diff --git a/gnu/services/cups.scm b/gnu/services/cups.scm
index 27aac7a16ac..e2102a07f8b 100644
--- a/gnu/services/cups.scm
+++ b/gnu/services/cups.scm
@@ -22,6 +22,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Service defininition for the CUPS printing system.
+;;;
+;;; Code:
+
 (define-module (gnu services cups)
   #:use-module (gnu services)
   #:use-module (gnu services shepherd)
@@ -47,12 +53,6 @@
             operation-access-control
             method-access-control))
 
-;;; Commentary:
-;;;
-;;; Service defininition for the CUPS printing system.
-;;;
-;;; Code:
-
 (define %cups-accounts
   (list (or
          ;; The "lp" group should already exist; try to reuse it.
diff --git a/gnu/services/databases.scm b/gnu/services/databases.scm
index 6742032f112..9ee30192eb5 100644
--- a/gnu/services/databases.scm
+++ b/gnu/services/databases.scm
@@ -28,6 +28,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Database services.
+;;;
+;;; Code:
+
 (define-module (gnu services databases)
   #:use-module (gnu services)
   #:use-module (gnu services base)
@@ -106,12 +112,6 @@
             redis-configuration?
             redis-service-type))
 
-;;; Commentary:
-;;;
-;;; Database services.
-;;;
-;;; Code:
-
 (define %default-postgres-hba
   (plain-file "pg_hba.conf"
               "
diff --git a/gnu/services/desktop.scm b/gnu/services/desktop.scm
index c9fe5024319..e481361b9e6 100644
--- a/gnu/services/desktop.scm
+++ b/gnu/services/desktop.scm
@@ -40,6 +40,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module contains service definitions for a "desktop" environment.
+;;;
+;;; Code:
+
 (define-module (gnu services desktop)
   #:use-module ((gnu home services utils) #:select (object->camel-case-string))
   #:use-module (gnu services)
@@ -243,12 +249,6 @@
 
             %desktop-services))
 
-;;; Commentary:
-;;;
-;;; This module contains service definitions for a "desktop" environment.
-;;;
-;;; Code:
-
 
 ;;;
 ;;; Helpers.
diff --git a/gnu/services/getmail.scm b/gnu/services/getmail.scm
index b44ca2ae3de..bea61d21a00 100644
--- a/gnu/services/getmail.scm
+++ b/gnu/services/getmail.scm
@@ -16,6 +16,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Service for the getmail mail retriever.
+;;;
+;;; Code:
+
 (define-module (gnu services getmail)
   #:use-module (gnu services)
   #:use-module (gnu services base)
@@ -41,12 +47,6 @@
             getmail-configuration
             getmail-service-type))
 
-;;; Commentary:
-;;;
-;;; Service for the getmail mail retriever.
-;;;
-;;; Code:
-
 (define (uglify-field-name field-name)
   (let ((str (symbol->string field-name)))
     (string-join (string-split (if (string-suffix? "?" str)
diff --git a/gnu/services/guix.scm b/gnu/services/guix.scm
index adf4990fde4..93f526d1c08 100644
--- a/gnu/services/guix.scm
+++ b/gnu/services/guix.scm
@@ -19,6 +19,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;;; Commentary:
+;;;
+;;; Services specifically related to GNU Guix.
+;;;
+;;;; Code:
+
 (define-module (gnu services guix)
   #:use-module (srfi srfi-1)
   #:use-module (ice-9 match)
@@ -165,12 +171,6 @@
             shared-cache-configuration
             user-cache))
 
-;;;; Commentary:
-;;;
-;;; Services specifically related to GNU Guix.
-;;;
-;;;; Code:
-
 (define-record-type* <guix-build-coordinator-configuration>
   guix-build-coordinator-configuration make-guix-build-coordinator-configuration
   guix-build-coordinator-configuration?
diff --git a/gnu/services/herd.scm b/gnu/services/herd.scm
index d276ba1b74c..777a8f8a3ae 100644
--- a/gnu/services/herd.scm
+++ b/gnu/services/herd.scm
@@ -18,6 +18,15 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provides an interface to the GNU Shepherd, similar to the
+;;; 'herd' command.  Essentially it implements a subset of the (shepherd comm)
+;;; module, but focusing only on the parts relevant to 'guix system
+;;; reconfigure'.
+;;;
+;;; Code:
+
 (define-module (gnu services herd)
   #:use-module (srfi srfi-1)
   #:use-module (srfi srfi-9)
@@ -63,15 +72,6 @@
             restart-service
             wait-for-service))
 
-;;; Commentary:
-;;;
-;;; This module provides an interface to the GNU Shepherd, similar to the
-;;; 'herd' command.  Essentially it implements a subset of the (shepherd comm)
-;;; module, but focusing only on the parts relevant to 'guix system
-;;; reconfigure'.
-;;;
-;;; Code:
-
 (define %shepherd-socket-file
   (let ((uid (getuid)))
     (make-parameter (if (zero? uid)     ;root
diff --git a/gnu/services/hurd.scm b/gnu/services/hurd.scm
index 1ee38e8cd01..53fdfb86043 100644
--- a/gnu/services/hurd.scm
+++ b/gnu/services/hurd.scm
@@ -16,6 +16,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module implements services for the Hurd.
+;;;
+;;; Code:
+
 (define-module (gnu services hurd)
   #:use-module (gnu packages admin)
   #:use-module (gnu packages hurd)
@@ -33,12 +39,6 @@
             hurd-login-configuration
             hurd-login-service-type))
 
-;;; Commentary:
-;;;
-;;; This module implements services for the Hurd.
-;;;
-;;; Code:
-
 ;;;
 ;;; The Hurd VGA console service.
 ;;;
diff --git a/gnu/services/lirc.scm b/gnu/services/lirc.scm
index 92784b65ca6..923cf83137a 100644
--- a/gnu/services/lirc.scm
+++ b/gnu/services/lirc.scm
@@ -17,6 +17,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; LIRC service.
+;;;
+;;; Code:
+
 (define-module (gnu services lirc)
   #:use-module (gnu services)
   #:use-module (gnu services shepherd)
@@ -30,12 +36,6 @@
             lirc-service  ; deprecated
             lirc-service-type))
 
-;;; Commentary:
-;;;
-;;; LIRC service.
-;;;
-;;; Code:
-
 (define-record-type* <lirc-configuration>
   lirc-configuration make-lirc-configuration
   lirc-configuation?
diff --git a/gnu/services/mail.scm b/gnu/services/mail.scm
index d31cad5645d..93eea095853 100644
--- a/gnu/services/mail.scm
+++ b/gnu/services/mail.scm
@@ -27,6 +27,13 @@
 ;;;
 ;;; Some of the help text was taken from the default dovecot.conf files.
 
+;;; Commentary:
+;;;
+;;; This module provides service definitions for the Dovecot POP3 and IMAP
+;;; mail server.
+;;;
+;;; Code:
+
 (define-module (gnu services mail)
   #:use-module (gnu services)
   #:use-module (gnu services base)
@@ -105,13 +112,6 @@
             %default-rspamd-config-file
             %default-rspamd-group))
 
-;;; Commentary:
-;;;
-;;; This module provides service definitions for the Dovecot POP3 and IMAP
-;;; mail server.
-;;;
-;;; Code:
-
 (define (uglify-field-name field-name)
   (let ((str (symbol->string field-name)))
     (string-join (string-split (if (string-suffix? "?" str)
diff --git a/gnu/services/mcron.scm b/gnu/services/mcron.scm
index 68d02ef4d7c..c8099480b84 100644
--- a/gnu/services/mcron.scm
+++ b/gnu/services/mcron.scm
@@ -18,6 +18,21 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module implements a service that to run instances of GNU mcron, a
+;;; periodic job execution daemon.  Example of a service:
+;;
+;;  (service mcron-service-type
+;;           (mcron-configuration
+;;            (jobs (list #~(job next-second-from
+;;                               (lambda ()
+;;                                 (call-with-output-file "/dev/console"
+;;                                   (lambda (port)
+;;                                     (display "hello!\n" port)))))))))
+;;;
+;;; Code:
+
 (define-module (gnu services mcron)
   #:use-module (gnu services)
   #:use-module (gnu services shepherd)
@@ -39,21 +54,6 @@
 
             mcron-service-type))
 
-;;; Commentary:
-;;;
-;;; This module implements a service that to run instances of GNU mcron, a
-;;; periodic job execution daemon.  Example of a service:
-;;
-;;  (service mcron-service-type
-;;           (mcron-configuration
-;;            (jobs (list #~(job next-second-from
-;;                               (lambda ()
-;;                                 (call-with-output-file "/dev/console"
-;;                                   (lambda (port)
-;;                                     (display "hello!\n" port)))))))))
-;;;
-;;; Code:
-
 ;; Configuration of mcron.
 ;; XXX: 'define-configuration' cannot be used here due to the need for
 ;; 'thunked' and 'innate' fields as well as 'this-mcron-configuration'.
diff --git a/gnu/services/messaging.scm b/gnu/services/messaging.scm
index 0be175d8af2..79c8d2a312c 100644
--- a/gnu/services/messaging.scm
+++ b/gnu/services/messaging.scm
@@ -22,6 +22,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Messaging services.
+;;;
+;;; Code:
+
 (define-module (gnu services messaging)
   #:use-module ((gnu home services utils) #:select (object->camel-case-string))
   #:use-module (gnu packages admin)
@@ -254,12 +260,6 @@
             zulip-irc-bridge-configuration
             zulip-irc-bridge-service-type))
 
-;;; Commentary:
-;;;
-;;; Messaging services.
-;;;
-;;; Code:
-
 (define-syntax define-all-configurations
   (lambda (stx)
     (define-syntax-rule (id ctx parts ...)
diff --git a/gnu/services/networking.scm b/gnu/services/networking.scm
index 752f3e3e890..5cce50010dd 100644
--- a/gnu/services/networking.scm
+++ b/gnu/services/networking.scm
@@ -41,6 +41,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Networking services.
+;;;
+;;; Code:
+
 (define-module (gnu services networking)
   #:use-module (gnu home services utils)
   #:use-module (gnu services)
@@ -308,12 +314,6 @@
             keepalived-configuration?
             keepalived-service-type))
 
-;;; Commentary:
-;;;
-;;; Networking services.
-;;;
-;;; Code:
-
 (define %unroutable-ipv4
   ;; Unroutable address, as per <https://www.rfc-editor.org/rfc/rfc5737>.
   "203.0.113.1")
diff --git a/gnu/services/nix.scm b/gnu/services/nix.scm
index 83ba78ce7e6..46f5c975056 100644
--- a/gnu/services/nix.scm
+++ b/gnu/services/nix.scm
@@ -17,6 +17,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provides a service definition for the Nix daemon.
+;;;
+;;; Code:
+
 (define-module (gnu services nix)
   #:use-module (gnu packages admin)
   #:use-module (gnu packages bash)
@@ -42,12 +48,6 @@
             nix-configuration
             nix-configuration?))
 
-;;; Commentary:
-;;;
-;;; This module provides a service definition for the Nix daemon.
-;;;
-;;; Code:
-
 (define-record-type* <nix-configuration>
   nix-configuration make-nix-configuration
   nix-configuration?
diff --git a/gnu/services/rsync.scm b/gnu/services/rsync.scm
index c9de8e710c0..fcdfed34db2 100644
--- a/gnu/services/rsync.scm
+++ b/gnu/services/rsync.scm
@@ -18,6 +18,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;;; Commentary:
+;;;
+;;; This module implements a service that to run instance of Rsync,
+;;; files synchronization tool.
+;;;
+;;;; Code:
+
 (define-module (gnu services rsync)
   #:use-module ((gnu build linux-container) #:select (%namespaces))
   #:use-module (gnu services)
@@ -50,13 +57,6 @@
 
             rsync-service-type))
 
-;;;; Commentary:
-;;;
-;;; This module implements a service that to run instance of Rsync,
-;;; files synchronization tool.
-;;;
-;;;; Code:
-
 (define-record-type* <rsync-configuration>
   rsync-configuration
   make-rsync-configuration
diff --git a/gnu/services/shepherd.scm b/gnu/services/shepherd.scm
index b1e8b040375..1a8eea67757 100644
--- a/gnu/services/shepherd.scm
+++ b/gnu/services/shepherd.scm
@@ -20,6 +20,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Instantiating system services as a shepherd configuration file.
+;;;
+;;; Code:
+
 (define-module (gnu services shepherd)
   #:use-module (guix ui)
   #:use-module (guix sets)
@@ -101,13 +107,6 @@
 
             assert-valid-graph))
 
-;;; Commentary:
-;;;
-;;; Instantiating system services as a shepherd configuration file.
-;;;
-;;; Code:
-
-
 (define-record-type* <shepherd-configuration>
   shepherd-configuration make-shepherd-configuration
   shepherd-configuration?
diff --git a/gnu/services/sound.scm b/gnu/services/sound.scm
index 4c319153448..cf535eb6e18 100644
--- a/gnu/services/sound.scm
+++ b/gnu/services/sound.scm
@@ -20,6 +20,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Sound services.
+;;;
+;;; Code:
+
 (define-module (gnu services sound)
   #:use-module (gnu services base)
   #:use-module (gnu services configuration)
@@ -79,12 +85,6 @@
             speakersafetyd-configuration?
             speakersafetyd-service-type))
 
-;;; Commentary:
-;;;
-;;; Sound services.
-;;;
-;;; Code:
-
 
 ;;;
 ;;; ALSA
diff --git a/gnu/services/ssh.scm b/gnu/services/ssh.scm
index e167d2f689f..a6ecd06d35a 100644
--- a/gnu/services/ssh.scm
+++ b/gnu/services/ssh.scm
@@ -24,6 +24,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module implements secure shell (SSH) services.
+;;;
+;;; OpenSSH.
+;;;
+
 (define-module (gnu services ssh)
   #:use-module (gnu packages ssh)
   #:use-module (gnu packages admin)
@@ -90,13 +97,6 @@
             webssh-service-type
             %webssh-configuration-nginx))
 
-;;; Commentary:
-;;;
-;;; This module implements secure shell (SSH) services.
-;;;
-;;; OpenSSH.
-;;;
-
 (define-record-type* <openssh-configuration>
   openssh-configuration make-openssh-configuration
   openssh-configuration?
diff --git a/gnu/services/syncthing.scm b/gnu/services/syncthing.scm
index 577672ab0c5..0d5e7cc8a94 100644
--- a/gnu/services/syncthing.scm
+++ b/gnu/services/syncthing.scm
@@ -18,6 +18,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provides a service definition for the syncthing service.
+;;;
+;;; Code:
+
 (define-module (gnu services syncthing)
   #:use-module (gnu packages syncthing)
   #:use-module (gnu services)
@@ -41,12 +47,6 @@
             syncthing-shepherd-service
             syncthing-files-service))
 
-;;; Commentary:
-;;;
-;;; This module provides a service definition for the syncthing service.
-;;;
-;;; Code:
-
 (define (bool->xml-string bool)
   ;; add compatibility for the short duration where #f was specified as
   ;; "false"
diff --git a/gnu/services/upnp.scm b/gnu/services/upnp.scm
index 16c32463534..70b242e5980 100644
--- a/gnu/services/upnp.scm
+++ b/gnu/services/upnp.scm
@@ -16,6 +16,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; UPnP services.
+;;;
+;;; Code:
+
 (define-module (gnu services upnp)
   #:use-module (gnu build linux-container)
   #:use-module (gnu packages admin)
@@ -54,12 +60,6 @@
             readymedia-activation
             readymedia-shepherd-service))
 
-;;; Commentary:
-;;;
-;;; UPnP services.
-;;;
-;;; Code:
-
 (define* (%readymedia-default-cache-directory #:key (home-service? #f))
   (if home-service?
       ".cache/readymedia"
diff --git a/gnu/services/version-control.scm b/gnu/services/version-control.scm
index 55af92c9f5a..8efa4996c5b 100644
--- a/gnu/services/version-control.scm
+++ b/gnu/services/version-control.scm
@@ -24,6 +24,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Version Control related services.
+;;;
+;;; Code:
+
 (define-module (gnu services version-control)
   #:use-module (gnu services)
   #:use-module (gnu services base)
@@ -135,12 +141,6 @@
 
             fossil-service-type))
 
-;;; Commentary:
-;;;
-;;; Version Control related services.
-;;;
-;;; Code:
-
 
 ;;;
 ;;; Git daemon.
diff --git a/gnu/services/web.scm b/gnu/services/web.scm
index 4a323dbd96e..351a7daf6dd 100644
--- a/gnu/services/web.scm
+++ b/gnu/services/web.scm
@@ -37,6 +37,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Web services.
+;;;
+;;; Code:
+
 (define-module (gnu services web)
   #:use-module (gnu services)
   #:use-module (gnu services shepherd)
@@ -390,12 +396,6 @@
 
             miniflux-service-type))
 
-;;; Commentary:
-;;;
-;;; Web services.
-;;;
-;;; Code:
-
 (define-record-type* <httpd-module>
   httpd-module make-httpd-module
   httpd-module?
diff --git a/gnu/services/xorg.scm b/gnu/services/xorg.scm
index a65dc20244c..5f8065b06d5 100644
--- a/gnu/services/xorg.scm
+++ b/gnu/services/xorg.scm
@@ -33,6 +33,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Services that relate to the X Window System.
+;;;
+;;; Code:
+
 (define-module (gnu services xorg)
   #:autoload   (gnu services sddm) (sddm-service-type)
   #:use-module (gnu artwork)
@@ -144,12 +150,6 @@
             handle-xorg-configuration
             set-xorg-configuration))
 
-;;; Commentary:
-;;;
-;;; Services that relate to the X Window System.
-;;;
-;;; Code:
-
 (define* (default-xorg-modules
            #:optional
            (system (or (and=>
diff --git a/gnu/system.scm b/gnu/system.scm
index bfcb4025a75..72f690a4050 100644
--- a/gnu/system.scm
+++ b/gnu/system.scm
@@ -32,6 +32,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module supports whole-system configuration.
+;;;
+;;; Code:
+
 (define-module (gnu system)
   #:use-module (guix inferior)
   #:use-module (guix store)
@@ -190,12 +196,6 @@
             %base-firmware
             %default-kernel-arguments))
 
-;;; Commentary:
-;;;
-;;; This module supports whole-system configuration.
-;;;
-;;; Code:
-
 (define* (bootable-kernel-arguments system root-device version)
   "Return a list of kernel arguments (gexps) to boot SYSTEM from ROOT-DEVICE.
 VERSION is the target version of the boot-parameters record."
diff --git a/gnu/system/accounts.scm b/gnu/system/accounts.scm
index 52dbbbf3a33..de91efe669a 100644
--- a/gnu/system/accounts.scm
+++ b/gnu/system/accounts.scm
@@ -17,6 +17,14 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Data structures representing user accounts and user groups.  This is meant
+;;; to be used both on the host side and at run time--e.g., in activation
+;;; snippets.
+;;;
+;;; Code:
+
 (define-module (gnu system accounts)
   #:use-module (guix records)
   #:use-module (ice-9 match)
@@ -55,15 +63,6 @@
 
             default-shell))
 
-
-;;; Commentary:
-;;;
-;;; Data structures representing user accounts and user groups.  This is meant
-;;; to be used both on the host side and at run time--e.g., in activation
-;;; snippets.
-;;;
-;;; Code:
-
 (define default-shell
   ;; Default shell for user accounts (a string or string-valued gexp).
   (make-parameter "/bin/sh"))
diff --git a/gnu/system/file-systems.scm b/gnu/system/file-systems.scm
index fd9065d2f6d..7ec2cd02594 100644
--- a/gnu/system/file-systems.scm
+++ b/gnu/system/file-systems.scm
@@ -21,6 +21,15 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Declaring file systems to be mounted.
+;;;
+;;; Note: this file system is used both in the Shepherd and on the "host
+;;; side", so it must not include (gnu packages …) modules.
+;;;
+;;; Code:
+
 (define-module (gnu system file-systems)
   #:use-module (ice-9 match)
   #:use-module (rnrs bytevectors)
@@ -109,15 +118,6 @@
             swap-space-priority
             swap-space-discard?))
 
-;;; Commentary:
-;;;
-;;; Declaring file systems to be mounted.
-;;;
-;;; Note: this file system is used both in the Shepherd and on the "host
-;;; side", so it must not include (gnu packages …) modules.
-;;;
-;;; Code:
-
 (eval-when (expand load eval)
   (define invalid-file-system-flags
     ;; Note: Keep in sync with 'mount-flags->bit-mask'.
diff --git a/gnu/system/hurd.scm b/gnu/system/hurd.scm
index 4d5a3d6799b..b57526f93c2 100644
--- a/gnu/system/hurd.scm
+++ b/gnu/system/hurd.scm
@@ -17,6 +17,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provides system-specifics for the GNU/Hurd operating system
+;;; and virtual machine.
+;;;
+;;; Code:
+
 (define-module (gnu system hurd)
   #:use-module (ice-9 match)
   #:use-module (guix gexp)
@@ -55,13 +62,6 @@
             %hurd-default-operating-system-kernel
             %setuid-programs/hurd))
 
-;;; Commentary:
-;;;
-;;; This module provides system-specifics for the GNU/Hurd operating system
-;;; and virtual machine.
-;;;
-;;; Code:
-
 (define %hurd-default-operating-system-kernel
   gnumach)
 
diff --git a/gnu/system/images/visionfive2.scm b/gnu/system/images/visionfive2.scm
index ee0682b6fcd..22f6545db12 100644
--- a/gnu/system/images/visionfive2.scm
+++ b/gnu/system/images/visionfive2.scm
@@ -17,6 +17,18 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;;  With this image, VisionFive2 can boot from MMC1 (MicroSD card) with
+;;;  SDIO3.0 boot mode (RPIO_1:L, RGPIO_0:H -- see [1]), in this case the
+;;;  board will use U-Boot from Guix System instead of the vendor U-Boot.
+;;;  Booting from eMMC and NVME is still work-in-progress.
+;;;
+;;; References:
+;;;  1. <https://doc-en.rvspace.org/VisionFive2/Boot_UG/VisionFive2_SDK_QSG/boot_mode_settings.html>
+;;;
+;;; Code:
+
 (define-module (gnu system images visionfive2)
   #:use-module (gnu bootloader)
   #:use-module (gnu bootloader u-boot)
@@ -46,18 +58,6 @@
             visionfive2-image-type
             visionfive2-barebones-raw-image))
 
-;;; Commentary:
-;;;
-;;;  With this image, VisionFive2 can boot from MMC1 (MicroSD card) with
-;;;  SDIO3.0 boot mode (RPIO_1:L, RGPIO_0:H -- see [1]), in this case the
-;;;  board will use U-Boot from Guix System instead of the vendor U-Boot.
-;;;  Booting from eMMC and NVME is still work-in-progress.
-;;;
-;;; References:
-;;;  1. <https://doc-en.rvspace.org/VisionFive2/Boot_UG/VisionFive2_SDK_QSG/boot_mode_settings.html>
-;;;
-;;; Code:
-
 (define visionfive2-barebones-os
   (operating-system
     (host-name "visionfive2")
diff --git a/gnu/system/install.scm b/gnu/system/install.scm
index 2f5d5d4b1c9..80f5a51fdae 100644
--- a/gnu/system/install.scm
+++ b/gnu/system/install.scm
@@ -24,6 +24,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provides an 'operating-system' definition for use on images
+;;; for USB sticks etc., for the installation of the GNU system.
+;;;
+;;; Code:
+
 (define-module (gnu system install)
   #:use-module ((guix licenses) #:prefix license:)
   #:use-module (gnu)
@@ -88,13 +95,6 @@
             wandboard-installation-os
             os-with-u-boot))
 
-;;; Commentary:
-;;;
-;;; This module provides an 'operating-system' definition for use on images
-;;; for USB sticks etc., for the installation of the GNU system.
-;;;
-;;; Code:
-
 
 ;;;
 ;;; Documentation service.
diff --git a/gnu/system/keyboard.scm b/gnu/system/keyboard.scm
index 5bd13a44be4..672fbcde8c6 100644
--- a/gnu/system/keyboard.scm
+++ b/gnu/system/keyboard.scm
@@ -16,6 +16,14 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provides a data structure to represent keyboard layouts
+;;; according to the XKB naming and classification (see the 'xkeyboard-config'
+;;; package).
+;;;
+;;; Code:
+
 (define-module (gnu system keyboard)
   #:use-module (guix gexp)
   #:use-module ((gnu packages xorg)
@@ -31,14 +39,6 @@
 
             keyboard-layout->console-keymap))
 
-;;; Commentary:
-;;;
-;;; This module provides a data structure to represent keyboard layouts
-;;; according to the XKB naming and classification (see the 'xkeyboard-config'
-;;; package).
-;;;
-;;; Code:
-
 (define-immutable-record-type <keyboard-layout>
   (%keyboard-layout name variant model options)
   keyboard-layout?
diff --git a/gnu/system/linux-initrd.scm b/gnu/system/linux-initrd.scm
index b56e6cf5d42..4ea0a59e935 100644
--- a/gnu/system/linux-initrd.scm
+++ b/gnu/system/linux-initrd.scm
@@ -20,6 +20,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Tools to build initial RAM disks (initrd's) for Linux-Libre, and in
+;;; particular initrd's that run Guile.
+;;;
+;;; Code:
+
 (define-module (gnu system linux-initrd)
   #:use-module (guix deprecation)
   #:use-module (guix gexp)
@@ -56,14 +63,6 @@
             base-initrd))
 
 
-;;; Commentary:
-;;;
-;;; Tools to build initial RAM disks (initrd's) for Linux-Libre, and in
-;;; particular initrd's that run Guile.
-;;;
-;;; Code:
-
-
 (define* (expression->initrd exp
                              #:key
                              (guile %guile-static-initrd)
diff --git a/gnu/system/locale.scm b/gnu/system/locale.scm
index 37f6456e673..866e198b2f6 100644
--- a/gnu/system/locale.scm
+++ b/gnu/system/locale.scm
@@ -18,6 +18,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Locale definitions, and compilation thereof.
+;;;
+;;; Code:
+
 (define-module (gnu system locale)
   #:use-module (guix gexp)
   #:use-module (guix store)
@@ -43,12 +49,6 @@
 
             glibc-supported-locales))
 
-;;; Commentary:
-;;;
-;;; Locale definitions, and compilation thereof.
-;;;
-;;; Code:
-
 (define-record-type* <locale-definition> locale-definition
   make-locale-definition
   locale-definition?
diff --git a/gnu/system/mapped-devices.scm b/gnu/system/mapped-devices.scm
index 8c32c3d3d4d..e7bb3eae726 100644
--- a/gnu/system/mapped-devices.scm
+++ b/gnu/system/mapped-devices.scm
@@ -19,6 +19,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module supports "device mapping", a concept implemented by Linux's
+;;; device-mapper.
+;;;
+;;; Code:
+
 (define-module (gnu system mapped-devices)
   #:use-module (guix gexp)
   #:use-module (guix records)
@@ -72,13 +79,6 @@
             raid-device-mapping
             lvm-device-mapping))
 
-;;; Commentary:
-;;;
-;;; This module supports "device mapping", a concept implemented by Linux's
-;;; device-mapper.
-;;;
-;;; Code:
-
 (define-record-type* <mapped-device> %mapped-device
   make-mapped-device
   mapped-device?
diff --git a/gnu/system/nss.scm b/gnu/system/nss.scm
index 930f556e5e5..9beadf05cab 100644
--- a/gnu/system/nss.scm
+++ b/gnu/system/nss.scm
@@ -16,6 +16,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Bindings for libc's name service switch (NSS) configuration.
+;;;
+;;; Code:
+
 (define-module (gnu system nss)
   #:use-module (rnrs enums)
   #:use-module (guix records)
@@ -38,12 +44,6 @@
 
             name-service-switch->string))
 
-;;; Commentary:
-;;;
-;;; Bindings for libc's name service switch (NSS) configuration.
-;;;
-;;; Code:
-
 (define-record-type* <name-service> name-service
   make-name-service
   name-service?
diff --git a/gnu/system/pam.scm b/gnu/system/pam.scm
index 83cf74d58ce..935419544a8 100644
--- a/gnu/system/pam.scm
+++ b/gnu/system/pam.scm
@@ -17,6 +17,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Configuration of the pluggable authentication modules (PAM).
+;;;
+;;; Code:
+
 (define-module (gnu system pam)
   #:use-module (guix records)
   #:use-module (guix derivations)
@@ -69,12 +75,6 @@
             pam-root-service-type
             pam-root-service))
 
-;;; Commentary:
-;;;
-;;; Configuration of the pluggable authentication modules (PAM).
-;;;
-;;; Code:
-
 ;; PAM services (see
 ;; <http://www.linux-pam.org/Linux-PAM-html/sag-configuration-file.html>.)
 (define-record-type* <pam-service> pam-service
diff --git a/gnu/system/privilege.scm b/gnu/system/privilege.scm
index fe6e60ad7c4..26d9b2fe289 100644
--- a/gnu/system/privilege.scm
+++ b/gnu/system/privilege.scm
@@ -17,6 +17,14 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Data structures representing privileged programs: binaries with additional
+;;; permissions such as setuid/setgid, or POSIX capabilities.  This is meant to
+;;; be used both on the host side and at run time--e.g., in activation snippets.
+;;;
+;;; Code:
+
 (define-module (gnu system privilege)
   #:use-module (guix records)
   #:export (privileged-program
@@ -30,14 +38,6 @@
 
             file-like->setuid-program))
 
-;;; Commentary:
-;;;
-;;; Data structures representing privileged programs: binaries with additional
-;;; permissions such as setuid/setgid, or POSIX capabilities.  This is meant to
-;;; be used both on the host side and at run time--e.g., in activation snippets.
-;;;
-;;; Code:
-
 (define-record-type* <privileged-program>
   privileged-program make-privileged-program
   privileged-program?
diff --git a/gnu/system/setuid.scm b/gnu/system/setuid.scm
index 097797ce8d7..dab31dad5d2 100644
--- a/gnu/system/setuid.scm
+++ b/gnu/system/setuid.scm
@@ -17,6 +17,14 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Do not use this module in new code.  It used to define data structures
+;;; representing setuid/setgid programs, but is now a mere compatibility shim
+;;; wrapping a subset of (gnu system privilege).
+;;;
+;;; Code:
+
 (define-module (gnu system setuid)
   #:use-module (gnu system privilege)
   #:use-module (ice-9 match)
@@ -30,14 +38,6 @@
             setuid-program-user
             setuid-program-group))
 
-;;; Commentary:
-;;;
-;;; Do not use this module in new code.  It used to define data structures
-;;; representing setuid/setgid programs, but is now a mere compatibility shim
-;;; wrapping a subset of (gnu system privilege).
-;;;
-;;; Code:
-
 (define-syntax setuid-program
   (lambda (fields)
     (syntax-case fields ()
diff --git a/gnu/system/shadow.scm b/gnu/system/shadow.scm
index f864a4f692e..2cce6e828f6 100644
--- a/gnu/system/shadow.scm
+++ b/gnu/system/shadow.scm
@@ -21,6 +21,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Utilities for configuring the Shadow tool suite ('login', 'passwd', etc.)
+;;;
+;;; Code:
+
 (define-module (gnu system shadow)
   #:use-module ((guix diagnostics) #:select (formatted-message))
   #:use-module (guix records)
@@ -97,12 +103,6 @@
 
             subids-service-type))
 
-;;; Commentary:
-;;;
-;;; Utilities for configuring the Shadow tool suite ('login', 'passwd', etc.)
-;;;
-;;; Code:
-
 ;; Change the default shell used by new <user-account> records.
 (default-shell (file-append bash "/bin/bash"))
 
diff --git a/gnu/system/vm.scm b/gnu/system/vm.scm
index a6a05862a5c..c4fc3e84745 100644
--- a/gnu/system/vm.scm
+++ b/gnu/system/vm.scm
@@ -22,6 +22,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Tools to evaluate build expressions within virtual machines.
+;;;
+;;; Code:
+
 (define-module (gnu system vm)
   #:use-module (guix config)
   #:use-module (guix store)
@@ -91,12 +97,6 @@
             common-qemu-options))
 
 
-;;; Commentary:
-;;;
-;;; Tools to evaluate build expressions within virtual machines.
-;;;
-;;; Code:
-
 ;; By default, the msize value is 8 KiB, which according to QEMU is
 ;; insufficient and would degrade performance.  The msize value should roughly
 ;; match the bandwidth of the system's IO (see:
diff --git a/gnu/tests.scm b/gnu/tests.scm
index 3b12726de82..ab74ed5874e 100644
--- a/gnu/tests.scm
+++ b/gnu/tests.scm
@@ -19,6 +19,15 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provides the infrastructure to run operating system tests.
+;;; The most important part of that is tools to instrument the OS under test,
+;;; essentially allowing it to run in a virtual machine controlled by the host
+;;; system--hence the name "marionette".
+;;;
+;;; Code:
+
 (define-module (gnu tests)
   #:use-module (guix gexp)
   #:use-module (guix diagnostics)
@@ -65,15 +74,6 @@
             fold-system-tests
             all-system-tests))
 
-;;; Commentary:
-;;;
-;;; This module provides the infrastructure to run operating system tests.
-;;; The most important part of that is tools to instrument the OS under test,
-;;; essentially allowing it to run in a virtual machine controlled by the host
-;;; system--hence the name "marionette".
-;;;
-;;; Code:
-
 (define %default-marionette-device
   ;; Default marionette device in the guest.
   "/dev/virtio-ports/org.gnu.guix.port.0")
diff --git a/gnu/tests/image.scm b/gnu/tests/image.scm
index be6852cae0a..3e7629c3b68 100644
--- a/gnu/tests/image.scm
+++ b/gnu/tests/image.scm
@@ -16,6 +16,17 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provides tests for the image creation process that is
+;;; performed by "genimage" under the hood.
+;;;
+;;; The image partitionment is checked using Guile-Parted.  The content of the
+;;; images is out of the scope of this module.  Other test modules such as
+;;; (gnu tests installation) make sure that the produced images are viable.
+;;;
+;;; Code:
+
 (define-module (gnu tests image)
   #:use-module (gnu)
   #:use-module (gnu image)
@@ -30,17 +41,6 @@
   #:use-module (ice-9 format)
   #:export (%test-images))
 
-;;; Commentary:
-;;;
-;;; This module provides tests for the image creation process that is
-;;; performed by "genimage" under the hood.
-;;;
-;;; The image partitionment is checked using Guile-Parted.  The content of the
-;;; images is out of the scope of this module.  Other test modules such as
-;;; (gnu tests installation) make sure that the produced images are viable.
-;;;
-;;; Code:
-
 ;; A dummy initializer creating a simple file in the partition.
 (define dummy-initializer
   #~(lambda* (root . rest)
diff --git a/gnu/tests/install.scm b/gnu/tests/install.scm
index 91ab59ce8d2..2c336ce4e94 100644
--- a/gnu/tests/install.scm
+++ b/gnu/tests/install.scm
@@ -21,6 +21,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Test the installation of Guix using the documented approach at the
+;;; command line.
+;;;
+;;; Code:
+
 (define-module (gnu tests install)
   #:use-module (gnu)
   #:use-module (gnu bootloader extlinux)
@@ -89,13 +96,6 @@
             %test-gui-installed-os-encrypted
             %test-gui-installed-desktop-os-encrypted))
 
-;;; Commentary:
-;;;
-;;; Test the installation of Guix using the documented approach at the
-;;; command line.
-;;;
-;;; Code:
-
 (define-os-with-source (%minimal-os %minimal-os-source)
   ;; The OS we want to install.
   (use-modules (gnu) (gnu tests) (srfi srfi-1))
diff --git a/gnu/tests/linux-modules.scm b/gnu/tests/linux-modules.scm
index 69cb0132670..8f4d79445bd 100644
--- a/gnu/tests/linux-modules.scm
+++ b/gnu/tests/linux-modules.scm
@@ -19,6 +19,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Test <operating-system> kernel-loadable-modules.
+;;;
+;;; Code:
+
 (define-module (gnu tests linux-modules)
   #:use-module (gnu packages linux)
   #:use-module (gnu services)
@@ -40,12 +46,6 @@
             %test-loadable-kernel-modules-service-1
             %test-loadable-kernel-modules-service-2))
 
-;;; Commentary:
-;;;
-;;; Test <operating-system> kernel-loadable-modules.
-;;;
-;;; Code:
-
 (define* (modules-loaded?-program os modules)
   "Return an executable store item that, upon being evaluated, will verify
 that MODULES are actually loaded."
diff --git a/gnu/tests/package-management.scm b/gnu/tests/package-management.scm
index c5102fff74d..869494b7e11 100644
--- a/gnu/tests/package-management.scm
+++ b/gnu/tests/package-management.scm
@@ -16,6 +16,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provides a test definition for the nix-daemon
+;;;
+;;; Code:
+
 (define-module (gnu tests package-management)
   #:use-module (gnu packages base)
   #:use-module (gnu packages package-management)
@@ -29,12 +35,6 @@
   #:use-module (guix packages)
   #:export (%test-nix))
 
-;;; Commentary:
-;;;
-;;; This module provides a test definition for the nix-daemon
-;;;
-;;; Code:
-
 (define* (run-nix-test name test-os)
   "Run tests in TEST-OS, which has nix-daemon running."
   (define os
diff --git a/gnu/tests/reconfigure.scm b/gnu/tests/reconfigure.scm
index 77cbe16a9ca..1ffb75ad2ac 100644
--- a/gnu/tests/reconfigure.scm
+++ b/gnu/tests/reconfigure.scm
@@ -17,6 +17,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Test in-place system reconfiguration: advancing the system generation on a
+;;; running instance of the Guix System.
+;;;
+;;; Code:
+
 (define-module (gnu tests reconfigure)
   #:use-module (gnu bootloader)
   #:use-module (gnu services)
@@ -38,13 +45,6 @@
             %test-upgrade-kexec
             %test-install-bootloader))
 
-;;; Commentary:
-;;;
-;;; Test in-place system reconfiguration: advancing the system generation on a
-;;; running instance of the Guix System.
-;;;
-;;; Code:
-
 (define* (run-switch-to-system-test)
   "Run a test of an OS running SWITCH-SYSTEM-PROGRAM, which creates a new
 generation of the system profile."
diff --git a/guix/amd-gpu.scm b/guix/amd-gpu.scm
index d16fea2a053..65d1882ef59 100644
--- a/guix/amd-gpu.scm
+++ b/guix/amd-gpu.scm
@@ -17,18 +17,18 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
-(define-module (guix amd-gpu)
-  #:autoload (guix packages) (this-package package-properties)
-  #:export (%default-amd-gpu-targets
-            current-amd-gpu-targets
-            current-amd-gpu-targets-string))
-
 ;;; Commentary:
 ;;;
 ;;; This module provides helpers for packages targeting AMD GPUs.
 ;;;
 ;;; Code:
 
+(define-module (guix amd-gpu)
+  #:autoload (guix packages) (this-package package-properties)
+  #:export (%default-amd-gpu-targets
+            current-amd-gpu-targets
+            current-amd-gpu-targets-string))
+
 (define %default-amd-gpu-targets
   '("gfx908" "gfx90a" "gfx942" "gfx1030" "gfx1100" "gfx1101" "gfx1200" "gfx1201"))
 
diff --git a/guix/android-repo-download.scm b/guix/android-repo-download.scm
index 7b63d388fce..2af88fefd30 100644
--- a/guix/android-repo-download.scm
+++ b/guix/android-repo-download.scm
@@ -20,6 +20,15 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; An <origin> method that fetches a specific commit from an Android repo
+;;; repository.
+;;; The repository's manifest (URL and revision) can be specified with a
+;;; <android-repo-reference> object.
+;;;
+;;; Code:
+
 (define-module (guix android-repo-download)
   #:use-module (guix gexp)
   #:use-module (guix store)
@@ -39,15 +48,6 @@
             android-repo-version
             android-repo-file-name))
 
-;;; Commentary:
-;;;
-;;; An <origin> method that fetches a specific commit from an Android repo
-;;; repository.
-;;; The repository's manifest (URL and revision) can be specified with a
-;;; <android-repo-reference> object.
-;;;
-;;; Code:
-
 (define-record-type* <android-repo-reference>
   android-repo-reference make-android-repo-reference
   android-repo-reference?
diff --git a/guix/base32.scm b/guix/base32.scm
index dd18a796f23..543d1cbca77 100644
--- a/guix/base32.scm
+++ b/guix/base32.scm
@@ -16,6 +16,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; A generic, customizable to convert bytevectors to/from a base32
+;;; representation.
+;;;
+;;; Code:
+
 (define-module (guix base32)
   #:use-module (srfi srfi-34)
   #:use-module (srfi srfi-35)
@@ -34,13 +41,6 @@
             invalid-base32-character-value
             invalid-base32-character-string))
 
-;;; Commentary:
-;;;
-;;; A generic, customizable to convert bytevectors to/from a base32
-;;; representation.
-;;;
-;;; Code:
-
 (define-syntax bit-field
   (lambda (s)
     ;; This inline version of 'bit-field' assumes that START and END are
diff --git a/guix/build-system/channel.scm b/guix/build-system/channel.scm
index 7b906dea28b..fe59520d1cc 100644
--- a/guix/build-system/channel.scm
+++ b/guix/build-system/channel.scm
@@ -16,14 +16,6 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
-(define-module (guix build-system channel)
-  #:use-module ((guix store) #:select (%store-monad store-lift))
-  #:use-module ((guix gexp) #:select (lower-object))
-  #:use-module (guix monads)
-  #:use-module (guix channels)
-  #:use-module (guix build-system)
-  #:export (channel-build-system))
-
 ;;; Commentary:
 ;;;
 ;;; The "channel" build system lets you build Guix instances from channel
@@ -32,6 +24,14 @@
 ;;;
 ;;; Code:
 
+(define-module (guix build-system channel)
+  #:use-module ((guix store) #:select (%store-monad store-lift))
+  #:use-module ((guix gexp) #:select (lower-object))
+  #:use-module (guix monads)
+  #:use-module (guix channels)
+  #:use-module (guix build-system)
+  #:export (channel-build-system))
+
 (define latest-channel-instances*
   (store-lift latest-channel-instances))
 
diff --git a/guix/build/android-repo.scm b/guix/build/android-repo.scm
index db8c4d127ba..531f5e8c40b 100644
--- a/guix/build/android-repo.scm
+++ b/guix/build/android-repo.scm
@@ -17,12 +17,6 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
-(define-module (guix build android-repo)
-  #:use-module (guix build utils)
-  #:use-module (srfi srfi-34)
-  #:use-module (ice-9 format)
-  #:export (android-repo-fetch))
-
 ;;; Commentary:
 ;;;
 ;;; This is the build-side support code of (guix android-repo-download).
@@ -31,6 +25,12 @@
 ;;;
 ;;; Code:
 
+(define-module (guix build android-repo)
+  #:use-module (guix build utils)
+  #:use-module (srfi srfi-34)
+  #:use-module (ice-9 format)
+  #:export (android-repo-fetch))
+
 (define* (android-repo-fetch manifest-url manifest-revision directory
                              #:key (git-repo-command "git-repo"))
   "Fetch packages according to the manifest at MANIFEST-URL with
diff --git a/guix/build/bournish.scm b/guix/build/bournish.scm
index 31fc493b09b..9ec76a0378d 100644
--- a/guix/build/bournish.scm
+++ b/guix/build/bournish.scm
@@ -18,6 +18,14 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This is a super minimal Bourne-like shell language for Guile.  It is meant
+;;; to be used at the REPL as a rescue shell.  In a way, this is to Guile what
+;;; eshell is to Emacs.
+;;;
+;;; Code:
+
 (define-module (guix build bournish)
   #:use-module (system base language)
   #:use-module (system base compile)
@@ -31,14 +39,6 @@
   #:use-module (srfi srfi-26)
   #:export (%bournish-language))
 
-;;; Commentary:
-;;;
-;;; This is a super minimal Bourne-like shell language for Guile.  It is meant
-;;; to be used at the REPL as a rescue shell.  In a way, this is to Guile what
-;;; eshell is to Emacs.
-;;;
-;;; Code:
-
 (define (expand-variable str)
   "Return STR or code to obtain the value of the environment variable STR
 refers to."
diff --git a/guix/build/bzr.scm b/guix/build/bzr.scm
index dede5e031ab..1dcaa7b61f8 100644
--- a/guix/build/bzr.scm
+++ b/guix/build/bzr.scm
@@ -16,10 +16,6 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
-(define-module (guix build bzr)
-  #:use-module (guix build utils)
-  #:export (bzr-fetch))
-
 ;;; Commentary:
 ;;;
 ;;; This is the build-side support code of (guix bzr-download).  It allows a
@@ -27,6 +23,10 @@
 ;;;
 ;;; Code:
 
+(define-module (guix build bzr)
+  #:use-module (guix build utils)
+  #:export (bzr-fetch))
+
 (define* (bzr-fetch url revision directory
                     #:key (bzr-command "brz"))
   "Fetch REVISION from URL into DIRECTORY.  REVISION must be a valid Bazaar
diff --git a/guix/build/compile.scm b/guix/build/compile.scm
index f90016b9ae8..03d6b5396bb 100644
--- a/guix/build/compile.scm
+++ b/guix/build/compile.scm
@@ -17,6 +17,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Support code to compile Guile code as efficiently as possible (with 2.2).
+;;;
+;;; Code:
+
 (define-module (guix build compile)
   #:use-module (srfi srfi-1)
   #:use-module (ice-9 match)
@@ -31,12 +37,6 @@
   #:use-module (language cps optimize)
   #:export (compile-files))
 
-;;; Commentary:
-;;;
-;;; Support code to compile Guile code as efficiently as possible (with 2.2).
-;;;
-;;; Code:
-
 (define (clear-keyword-arguments keywords args)
   "Set to #f the value associated with each of the KEYWORDS in ARGS."
   (let loop ((args   args)
diff --git a/guix/build/cvs.scm b/guix/build/cvs.scm
index 71110437475..2ad0beb0b6d 100644
--- a/guix/build/cvs.scm
+++ b/guix/build/cvs.scm
@@ -17,12 +17,6 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
-(define-module (guix build cvs)
-  #:use-module (guix build utils)
-  #:use-module (ice-9 regex)
-  #:use-module (ice-9 ftw)
-  #:export (cvs-fetch))
-
 ;;; Commentary:
 ;;;
 ;;; This is the build-side support code of (guix cvs-download).  It allows a
@@ -30,6 +24,12 @@
 ;;;
 ;;; Code:
 
+(define-module (guix build cvs)
+  #:use-module (guix build utils)
+  #:use-module (ice-9 regex)
+  #:use-module (ice-9 ftw)
+  #:export (cvs-fetch))
+
 (define (find-cvs-directories)
   (define (enter? path st result)
     (not (string-suffix? "/CVS" path)))
diff --git a/guix/build/debug-link.scm b/guix/build/debug-link.scm
index 80941df2fc7..4ea1f587ef1 100644
--- a/guix/build/debug-link.scm
+++ b/guix/build/debug-link.scm
@@ -16,6 +16,20 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provides tools to deal with '.gnu_debuglink' sections in ELF
+;;; files.  These sections are created by 'objcopy --add-gnu-debuglink' to
+;;; create separate debug files (info "(gdb) Separate Debug Files").
+;;;
+;;; The main facility of this module is 'graft-debug-links', which allows us
+;;; to update the cyclic redundancy check (CRC) that appears in
+;;; '.gnu_debuglink' sections when grafting, such that separate debug files
+;;; remain usable after grafting.  Failing to do that, GDB would complain
+;;; about CRC mismatch---see <https://issues.guix.gnu.org/19973>.
+;;;
+;;; Code:
+
 (define-module (guix build debug-link)
   #:use-module (guix elf)
   #:use-module ((guix build utils)
@@ -31,20 +45,6 @@
 
             graft-debug-links))
 
-;;; Commentary:
-;;;
-;;; This module provides tools to deal with '.gnu_debuglink' sections in ELF
-;;; files.  These sections are created by 'objcopy --add-gnu-debuglink' to
-;;; create separate debug files (info "(gdb) Separate Debug Files").
-;;;
-;;; The main facility of this module is 'graft-debug-links', which allows us
-;;; to update the cyclic redundancy check (CRC) that appears in
-;;; '.gnu_debuglink' sections when grafting, such that separate debug files
-;;; remain usable after grafting.  Failing to do that, GDB would complain
-;;; about CRC mismatch---see <https://issues.guix.gnu.org/19973>.
-;;;
-;;; Code:
-
 (define %crc32-table
   ;; CRC table taken from "(gdb) Separate Debug Files".
   ;; TODO: Wouldn't it be nice to generate it "from source" with a macro?
diff --git a/guix/build/download-nar.scm b/guix/build/download-nar.scm
index e1153e20275..796bc957a4e 100644
--- a/guix/build/download-nar.scm
+++ b/guix/build/download-nar.scm
@@ -16,6 +16,15 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Download a normalized archive or "nar", similar to what 'guix substitute'
+;;; does.  The intent here is to use substitute servers as content-addressed
+;;; mirrors of VCS checkouts.  This is mostly useful for users who have
+;;; disabled substitutes.
+;;;
+;;; Code:
+
 (define-module (guix build download-nar)
   #:use-module (guix build download)
   #:use-module ((guix serialization) #:hide (dump-port*))
@@ -28,15 +37,6 @@
   #:use-module (ice-9 match)
   #:export (download-nar))
 
-;;; Commentary:
-;;;
-;;; Download a normalized archive or "nar", similar to what 'guix substitute'
-;;; does.  The intent here is to use substitute servers as content-addressed
-;;; mirrors of VCS checkouts.  This is mostly useful for users who have
-;;; disabled substitutes.
-;;;
-;;; Code:
-
 (define (urls-for-item item)
   "Return the fallback nar URL for ITEM--e.g.,
 \"/gnu/store/cabbag3…-foo-1.2-checkout\"."
diff --git a/guix/build/download.scm b/guix/build/download.scm
index 8cf1814ea11..bf3f330b744 100644
--- a/guix/build/download.scm
+++ b/guix/build/download.scm
@@ -19,6 +19,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Fetch data such as tarballs over HTTP or FTP (builder-side code).
+;;;
+;;; Code:
+
 (define-module (guix build download)
   #:use-module (web uri)
   #:use-module (web http)
@@ -56,12 +62,6 @@
             nar-uri-abbreviation
             store-path-abbreviation))
 
-;;; Commentary:
-;;;
-;;; Fetch data such as tarballs over HTTP or FTP (builder-side code).
-;;;
-;;; Code:
-
 (define %http-receive-buffer-size
   ;; Size of the HTTP receive buffer.
   65536)
diff --git a/guix/build/elm-build-system.scm b/guix/build/elm-build-system.scm
index a2a54ab28c3..34c561452c5 100644
--- a/guix/build/elm-build-system.scm
+++ b/guix/build/elm-build-system.scm
@@ -16,26 +16,6 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
-(define-module (guix build elm-build-system)
-  #:use-module ((guix build gnu-build-system) #:prefix gnu:)
-  #:use-module (guix build utils)
-  #:use-module (guix build union)
-  #:use-module (ice-9 ftw)
-  #:use-module (ice-9 rdelim)
-  #:use-module (ice-9 regex)
-  #:use-module (ice-9 match)
-  #:use-module (ice-9 popen)
-  #:use-module (ice-9 vlist)
-  #:use-module (json)
-  #:use-module (srfi srfi-1)
-  #:use-module (srfi srfi-26)
-  #:use-module (srfi srfi-71)
-  #:export (%standard-phases
-            patch-application-dependencies
-            patch-json-string-escapes
-            read-offline-registry->vhash
-            elm-build))
-
 ;;; Commentary:
 ;;;
 ;;; Elm draws a sharp distinction between "projects" with `{"type":"package"}`
@@ -90,6 +70,26 @@
 ;;; Code:
 ;;;
 
+(define-module (guix build elm-build-system)
+  #:use-module ((guix build gnu-build-system) #:prefix gnu:)
+  #:use-module (guix build utils)
+  #:use-module (guix build union)
+  #:use-module (ice-9 ftw)
+  #:use-module (ice-9 rdelim)
+  #:use-module (ice-9 regex)
+  #:use-module (ice-9 match)
+  #:use-module (ice-9 popen)
+  #:use-module (ice-9 vlist)
+  #:use-module (json)
+  #:use-module (srfi srfi-1)
+  #:use-module (srfi srfi-26)
+  #:use-module (srfi srfi-71)
+  #:export (%standard-phases
+            patch-application-dependencies
+            patch-json-string-escapes
+            read-offline-registry->vhash
+            elm-build))
+
 (define %essential-elm-packages
   ;; elm/json isn't essential in a fundamental sense,
   ;; but it's required for a {"type":"application"},
diff --git a/guix/build/emacs-utils.scm b/guix/build/emacs-utils.scm
index 41914e7dcb0..e7763658da8 100644
--- a/guix/build/emacs-utils.scm
+++ b/guix/build/emacs-utils.scm
@@ -20,6 +20,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Tools to programmatically edit files using Emacs,
+;;; e.g. to replace entire s-expressions in elisp files.
+;;;
+;;; Code:
+
 (define-module (guix build emacs-utils)
   #:use-module (guix build utils)
   #:use-module (ice-9 format)
@@ -47,13 +54,6 @@
             emacs-substitute-sexps
             emacs-substitute-variables))
 
-;;; Commentary:
-;;;
-;;; Tools to programmatically edit files using Emacs,
-;;; e.g. to replace entire s-expressions in elisp files.
-;;;
-;;; Code:
-
 (define %emacs
   ;; The `emacs' command.
   (make-parameter "emacs"))
diff --git a/guix/build/git.scm b/guix/build/git.scm
index 98077fe8be3..d74364d0a69 100644
--- a/guix/build/git.scm
+++ b/guix/build/git.scm
@@ -17,6 +17,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This is the build-side support code of (guix git-download).  It allows a
+;;; Git repository to be cloned and checked out at a specific commit.
+;;;
+;;; Code:
+
 (define-module (guix build git)
   #:use-module (guix build utils)
   #:use-module ((guix build download)
@@ -30,13 +37,6 @@
   #:export (git-fetch
             git-fetch-with-fallback))
 
-;;; Commentary:
-;;;
-;;; This is the build-side support code of (guix git-download).  It allows a
-;;; Git repository to be cloned and checked out at a specific commit.
-;;;
-;;; Code:
-
 (define* (git-fetch url commit directory
                     #:key (git-command "git")
                     lfs? recursive?)
diff --git a/guix/build/gnu-dist.scm b/guix/build/gnu-dist.scm
index 59ac0012b80..4d6b19d3358 100644
--- a/guix/build/gnu-dist.scm
+++ b/guix/build/gnu-dist.scm
@@ -18,12 +18,6 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
-(define-module (guix build gnu-dist)
-  #:use-module (guix build utils)
-  #:use-module (guix build gnu-build-system)
-  #:use-module (srfi srfi-1)
-  #:export (%dist-phases))
-
 ;;; Commentary:
 ;;;
 ;;; Build phases to build a source tarball with the GNU build system, as with
@@ -31,6 +25,12 @@
 ;;;
 ;;; Code:
 
+(define-module (guix build gnu-dist)
+  #:use-module (guix build utils)
+  #:use-module (guix build gnu-build-system)
+  #:use-module (srfi srfi-1)
+  #:export (%dist-phases))
+
 (define* (build #:key build-before-dist? make-flags (dist-target "distcheck")
                 #:allow-other-keys
                 #:rest args)
diff --git a/guix/build/graft.scm b/guix/build/graft.scm
index 49fabfea174..77ae9a4b294 100644
--- a/guix/build/graft.scm
+++ b/guix/build/graft.scm
@@ -17,20 +17,6 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
-(define-module (guix build graft)
-  #:use-module (guix build utils)
-  #:use-module (guix build debug-link)
-  #:use-module (rnrs bytevectors)
-  #:use-module (ice-9 vlist)
-  #:use-module (ice-9 match)
-  #:use-module (ice-9 threads)
-  #:use-module (ice-9 binary-ports)
-  #:use-module (srfi srfi-1)   ; list library
-  #:use-module (srfi srfi-26)  ; cut and cute
-  #:export (replace-store-references
-            rewrite-directory
-            graft))
-
 ;;; Commentary:
 ;;;
 ;;; This module supports "grafts".  Grafting a directory means rewriting it,
@@ -44,6 +30,20 @@
 ;;;
 ;;; Code:
 
+(define-module (guix build graft)
+  #:use-module (guix build utils)
+  #:use-module (guix build debug-link)
+  #:use-module (rnrs bytevectors)
+  #:use-module (ice-9 vlist)
+  #:use-module (ice-9 match)
+  #:use-module (ice-9 threads)
+  #:use-module (ice-9 binary-ports)
+  #:use-module (srfi srfi-1)            ; list library
+  #:use-module (srfi srfi-26)           ; cut and cute
+  #:export (replace-store-references
+            rewrite-directory
+            graft))
+
 (define-constant hash-length %store-hash-string-length)
 
 (define nix-base32-char?
diff --git a/guix/build/gremlin.scm b/guix/build/gremlin.scm
index 2a74d51dd91..bd56cf83030 100644
--- a/guix/build/gremlin.scm
+++ b/guix/build/gremlin.scm
@@ -16,6 +16,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; A gremlin is sort-of like an elf, you know, and this module provides tools
+;;; to deal with dynamic-link information from ELF files.
+;;;
+;;; Code:
+
 (define-module (guix build gremlin)
   #:use-module (guix elf)
   #:use-module ((guix build utils) #:select (store-file-name?))
@@ -55,13 +62,6 @@
             validate-needed-in-runpath
             strip-runpath))
 
-;;; Commentary:
-;;;
-;;; A gremlin is sort-of like an elf, you know, and this module provides tools
-;;; to deal with dynamic-link information from ELF files.
-;;;
-;;; Code:
-
 (define-condition-type &elf-error &error
   elf-error?
   (elf elf-error-elf))
diff --git a/guix/build/hg.scm b/guix/build/hg.scm
index 0ffad7fa2dc..d0f71d0fd47 100644
--- a/guix/build/hg.scm
+++ b/guix/build/hg.scm
@@ -19,12 +19,6 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
-(define-module (guix build hg)
-  #:use-module (guix build utils)
-  #:use-module (srfi srfi-34)
-  #:use-module (ice-9 format)
-  #:export (hg-fetch))
-
 ;;; Commentary:
 ;;;
 ;;; This is the build-side support code of (guix hg-download).  It allows a
@@ -33,6 +27,12 @@
 ;;;
 ;;; Code:
 
+(define-module (guix build hg)
+  #:use-module (guix build utils)
+  #:use-module (srfi srfi-34)
+  #:use-module (ice-9 format)
+  #:export (hg-fetch))
+
 (define* (hg-fetch url changeset directory
                    #:key (hg-command "hg"))
   "Fetch CHANGESET from URL into DIRECTORY.  CHANGESET must be a valid
diff --git a/guix/build/lisp-utils.scm b/guix/build/lisp-utils.scm
index 09965c598e8..6c2d55e45b7 100644
--- a/guix/build/lisp-utils.scm
+++ b/guix/build/lisp-utils.scm
@@ -18,6 +18,14 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Tools to evaluate lisp programs within a lisp session, generate wrapper
+;;; systems for executables. Compile, test, and produce images for systems and
+;;; programs, and link them with their dependencies.
+;;;
+;;; Code:
+
 (define-module (guix build lisp-utils)
   #:use-module (ice-9 format)
   #:use-module (ice-9 hash-table)
@@ -45,14 +53,6 @@
             normalize-string
             library-output))
 
-;;; Commentary:
-;;;
-;;; Tools to evaluate lisp programs within a lisp session, generate wrapper
-;;; systems for executables. Compile, test, and produce images for systems and
-;;; programs, and link them with their dependencies.
-;;;
-;;; Code:
-
 (define %lisp
   ;; File name of the Lisp compiler.
   (make-parameter "lisp"))
diff --git a/guix/build/pack.scm b/guix/build/pack.scm
index 1b281014698..c68f2bffcdc 100644
--- a/guix/build/pack.scm
+++ b/guix/build/pack.scm
@@ -16,6 +16,15 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module contains build-side common procedures used by the host-side
+;;; (guix scripts pack) module, mostly to allow for code reuse.  Due to making
+;;; use of the (guix build store-copy) module, it transitively requires the
+;;; sqlite and gcrypt extensions to be available.
+;;;
+;;; Code:
+
 (define-module (guix build pack)
   #:use-module (gnu build install)
   #:use-module (guix build utils)
@@ -28,15 +37,6 @@
             populate-profile-root
             build-self-contained-tarball))
 
-;;; Commentary:
-
-;;; This module contains build-side common procedures used by the host-side
-;;; (guix scripts pack) module, mostly to allow for code reuse.  Due to making
-;;; use of the (guix build store-copy) module, it transitively requires the
-;;; sqlite and gcrypt extensions to be available.
-
-;;; Code:
-
 (define* (tar-base-options #:key tar compressor)
   "Return the base GNU tar options required to produce deterministic archives
 deterministically.  When TAR, a GNU tar command file name, is provided, the
diff --git a/guix/build/profiles.scm b/guix/build/profiles.scm
index b19d93f9714..bde78bfd024 100644
--- a/guix/build/profiles.scm
+++ b/guix/build/profiles.scm
@@ -16,6 +16,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Build a user profile (essentially the union of all the installed packages)
+;;; with its associated meta-data.
+;;;
+;;; Code:
+
 (define-module (guix build profiles)
   #:use-module (guix build union)
   #:use-module (guix build utils)
@@ -30,13 +37,6 @@
   #:export (ensure-writable-directory
             build-profile))
 
-;;; Commentary:
-;;;
-;;; Build a user profile (essentially the union of all the installed packages)
-;;; with its associated meta-data.
-;;;
-;;; Code:
-
 (define (abstract-profile profile)
   "Return a procedure that replaces PROFILE in VALUE with a reference to the
 'GUIX_PROFILE' environment variable.  This allows users to specify what the
diff --git a/guix/build/pyproject-build-system.scm b/guix/build/pyproject-build-system.scm
index f611afada24..3effdc61600 100644
--- a/guix/build/pyproject-build-system.scm
+++ b/guix/build/pyproject-build-system.scm
@@ -20,29 +20,6 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
-(define-module (guix build pyproject-build-system)
-  #:autoload (json builder) (scm->json scm->json-string)
-  #:use-module ((guix build gnu-build-system) #:prefix gnu:)
-  #:use-module (guix build utils)
-  #:use-module (guix build toml)
-  #:use-module (ice-9 match)
-  #:use-module (ice-9 ftw)
-  #:use-module (ice-9 format)
-  #:use-module (ice-9 rdelim)
-  #:use-module (ice-9 regex)
-  #:use-module (srfi srfi-1)
-  #:use-module (srfi srfi-2)
-  #:use-module (srfi srfi-26)
-  #:use-module (srfi srfi-34)
-  #:use-module (srfi srfi-35)
-  #:use-module (srfi srfi-71)
-  #:export (%standard-phases
-            add-installed-pythonpath
-            ensure-no-mtimes-pre-1980
-            site-packages
-            python-version
-            pyproject-build))
-
 ;;; Commentary:
 ;;;
 ;;; PEP 517-compatible build system for Python packages.
@@ -71,7 +48,29 @@
 ;;; overridden by #:backend-path.
 ;;;
 ;;; Code:
-;;;
+
+(define-module (guix build pyproject-build-system)
+  #:autoload (json builder) (scm->json scm->json-string)
+  #:use-module ((guix build gnu-build-system) #:prefix gnu:)
+  #:use-module (guix build utils)
+  #:use-module (guix build toml)
+  #:use-module (ice-9 match)
+  #:use-module (ice-9 ftw)
+  #:use-module (ice-9 format)
+  #:use-module (ice-9 rdelim)
+  #:use-module (ice-9 regex)
+  #:use-module (srfi srfi-1)
+  #:use-module (srfi srfi-2)
+  #:use-module (srfi srfi-26)
+  #:use-module (srfi srfi-34)
+  #:use-module (srfi srfi-35)
+  #:use-module (srfi srfi-71)
+  #:export (%standard-phases
+            add-installed-pythonpath
+            ensure-no-mtimes-pre-1980
+            site-packages
+            python-version
+            pyproject-build))
 
 ;; Copy these procedures from python-build-system as many packages
 ;; rely on these.
diff --git a/guix/build/store-copy.scm b/guix/build/store-copy.scm
index 657a91f324a..1abb1a5b01a 100644
--- a/guix/build/store-copy.scm
+++ b/guix/build/store-copy.scm
@@ -16,6 +16,15 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provides the tools to copy store items and their dependencies
+;;; to another store.  It relies on the availability of "reference graph"
+;;; files as produced by 'gexp->derivation' et al. with the
+;;; #:references-graphs parameter.
+;;;
+;;; Code:
+
 (define-module (guix build store-copy)
   #:use-module ((guix build utils) #:hide (copy-recursively))
   #:use-module (guix sets)
@@ -41,15 +50,6 @@
             copy-store-item
             populate-store))
 
-;;; Commentary:
-;;;
-;;; This module provides the tools to copy store items and their dependencies
-;;; to another store.  It relies on the availability of "reference graph"
-;;; files as produced by 'gexp->derivation' et al. with the
-;;; #:references-graphs parameter.
-;;;
-;;; Code:
-
 ;; Information about a store item as produced by #:references-graphs.
 (define-record-type <store-info>
   (store-info item deriver references)
diff --git a/guix/build/svn.scm b/guix/build/svn.scm
index ea01e7ee650..9b974792184 100644
--- a/guix/build/svn.scm
+++ b/guix/build/svn.scm
@@ -19,11 +19,6 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
-(define-module (guix build svn)
-  #:use-module (guix build utils)
-  #:use-module (srfi srfi-34)
-  #:export (svn-fetch))
-
 ;;; Commentary:
 ;;;
 ;;; This is the build-side support code of (guix svn-download).  It allows a
@@ -31,6 +26,11 @@
 ;;;
 ;;; Code:
 
+(define-module (guix build svn)
+  #:use-module (guix build utils)
+  #:use-module (srfi srfi-34)
+  #:export (svn-fetch))
+
 (define* (svn-fetch url revision directory
                     #:key (svn-command "svn")
                     (recursive? #t)
diff --git a/guix/build/syscalls.scm b/guix/build/syscalls.scm
index da3f56350f2..ee9711f41e3 100644
--- a/guix/build/syscalls.scm
+++ b/guix/build/syscalls.scm
@@ -27,6 +27,25 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provides bindings to libc's syscall wrappers.  It uses the
+;;; FFI, and thus requires a dynamically-linked Guile.
+;;;
+;;; Some syscalls are already defined in statically-linked Guile by applying
+;;; 'guile-linux-syscalls.patch'.
+;;;
+;;; Visibility of syscall's symbols shared between this module and static Guile
+;;; is a bit delicate. It is handled by 'define-as-needed' macro.
+;;;
+;;; This macro is used to export symbols in dynamic Guile context, and to
+;;; re-export them in static Guile context.
+;;;
+;;; This way, even if they don't appear in #:export list, it is safe to use
+;;; syscalls from this module in static or dynamic Guile context.
+;;;
+;;; Code:
+
 (define-module (guix build syscalls)
   #:use-module (system foreign)
   #:use-module (system base target)
@@ -228,25 +247,6 @@
             utmpx-entries
             (read-utmpx-from-port . read-utmpx)))
 
-;;; Commentary:
-;;;
-;;; This module provides bindings to libc's syscall wrappers.  It uses the
-;;; FFI, and thus requires a dynamically-linked Guile.
-;;;
-;;; Some syscalls are already defined in statically-linked Guile by applying
-;;; 'guile-linux-syscalls.patch'.
-;;;
-;;; Visibility of syscall's symbols shared between this module and static Guile
-;;; is a bit delicate. It is handled by 'define-as-needed' macro.
-;;;
-;;; This macro is used to export symbols in dynamic Guile context, and to
-;;; re-export them in static Guile context.
-;;;
-;;; This way, even if they don't appear in #:export list, it is safe to use
-;;; syscalls from this module in static or dynamic Guile context.
-;;;
-;;; Code:
-
 
 ;;;
 ;;; Packed structures.
diff --git a/guix/build/union.scm b/guix/build/union.scm
index ce6d030109b..bccdb00ce72 100644
--- a/guix/build/union.scm
+++ b/guix/build/union.scm
@@ -18,6 +18,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Build a directory that is the union of a set of directories, using
+;;; symbolic links.
+;;;
+;;; Code:
+
 (define-module (guix build union)
   #:use-module (ice-9 match)
   #:use-module (ice-9 format)
@@ -32,13 +39,6 @@
             relative-file-name
             symlink-relative))
 
-;;; Commentary:
-;;;
-;;; Build a directory that is the union of a set of directories, using
-;;; symbolic links.
-;;;
-;;; Code:
-
 ;; This code can be used with the bootstrap Guile, which is Guile 2.0, so
 ;; provide a compatibility layer.
 (cond-expand
diff --git a/guix/bzr-download.scm b/guix/bzr-download.scm
index cdd7f431397..ba812a9065c 100644
--- a/guix/bzr-download.scm
+++ b/guix/bzr-download.scm
@@ -17,6 +17,14 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; An <origin> method that fetches a specific revision from a Bazaar
+;;; repository.  The repository URL and revision identifier are specified with
+;;; a <bzr-reference> object.
+;;;
+;;; Code:
+
 (define-module (guix bzr-download)
   #:use-module (guix gexp)
   #:use-module (guix modules)   ;for 'source-module-closure'
@@ -32,14 +40,6 @@
 
             bzr-fetch))
 
-;;; Commentary:
-;;;
-;;; An <origin> method that fetches a specific revision from a Bazaar
-;;; repository.  The repository URL and revision identifier are specified with
-;;; a <bzr-reference> object.
-;;;
-;;; Code:
-
 (define-record-type* <bzr-reference>
   bzr-reference make-bzr-reference
   bzr-reference?
diff --git a/guix/cache.scm b/guix/cache.scm
index c1a12b17620..f3e5612a8e3 100644
--- a/guix/cache.scm
+++ b/guix/cache.scm
@@ -17,6 +17,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provides tools to manage a simple on-disk cache consisting of
+;;; individual files.
+;;;
+;;; Code:
+
 (define-module (guix cache)
   #:autoload   (guix build syscalls) (lock-file unlock-file)
   #:use-module (srfi srfi-19)
@@ -29,13 +36,6 @@
             remove-expired-cache-entries
             maybe-remove-expired-cache-entries))
 
-;;; Commentary:
-;;;
-;;; This module provides tools to manage a simple on-disk cache consisting of
-;;; individual files.
-;;;
-;;; Code:
-
 (define (obsolete? date now ttl)
   "Return #t if DATE is obsolete compared to NOW + TTL seconds."
   (time>? (subtract-duration now (make-time time-duration 0 ttl))
diff --git a/guix/channels.scm b/guix/channels.scm
index f216e201570..04cd2b8a2ed 100644
--- a/guix/channels.scm
+++ b/guix/channels.scm
@@ -22,6 +22,19 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module implements "channels."  A channel is usually a source of
+;;; package definitions.  There's a special channel, the 'guix' channel, that
+;;; provides all of Guix, including its commands and its documentation.
+;;; User-defined channels are expected to typically provide a bunch of .scm
+;;; files meant to be added to the '%package-search-path'.
+;;;
+;;; This module provides tools to fetch and update channels from a Git
+;;; repository and to build them.
+;;;
+;;; Code:
+
 (define-module (guix channels)
   #:autoload   (git commit) (commit-lookup
                              commit-id)
@@ -119,19 +132,6 @@
 
             channel-news-for-commit))
 
-;;; Commentary:
-;;;
-;;; This module implements "channels."  A channel is usually a source of
-;;; package definitions.  There's a special channel, the 'guix' channel, that
-;;; provides all of Guix, including its commands and its documentation.
-;;; User-defined channels are expected to typically provide a bunch of .scm
-;;; files meant to be added to the '%package-search-path'.
-;;;
-;;; This module provides tools to fetch and update channels from a Git
-;;; repository and to build them.
-;;;
-;;; Code:
-
 (define-record-type* <channel> channel make-channel
   channel?
   (name      channel-name)
diff --git a/guix/ci.scm b/guix/ci.scm
index b2077448b02..9a1f0c144a0 100644
--- a/guix/ci.scm
+++ b/guix/ci.scm
@@ -17,6 +17,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provides a client to the HTTP interface of the Hydra and
+;;; Cuirass continuous integration (CI) tools.
+;;;
+;;; Code:
+
 (define-module (guix ci)
   #:use-module (guix http-client)
   #:use-module (guix utils)
@@ -84,13 +91,6 @@
 
             channel-with-substitutes-available))
 
-;;; Commentary:
-;;;
-;;; This module provides a client to the HTTP interface of the Hydra and
-;;; Cuirass continuous integration (CI) tools.
-;;;
-;;; Code:
-
 (define (seconds->date seconds)
   "Given SECONDS, a number of seconds since 1970-01-01, return the
 corresponding date object."
diff --git a/guix/colors.scm b/guix/colors.scm
index 09bc7c60cc2..10cacfd1726 100644
--- a/guix/colors.scm
+++ b/guix/colors.scm
@@ -19,6 +19,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provides tools to produce colored output using ANSI escapes.
+;;;
+;;; Code:
+
 (define-module (guix colors)
   #:use-module (guix memoization)
   #:use-module (srfi srfi-1)
@@ -45,12 +51,6 @@
             file-hyperlink
             hyperlink))
 
-;;; Commentary:
-;;;
-;;; This module provides tools to produce colored output using ANSI escapes.
-;;;
-;;; Code:
-
 ;; Record type for "colors", which are actually lists of color attributes.
 (define-record-type <color>
   (make-color symbols ansi)
diff --git a/guix/combinators.scm b/guix/combinators.scm
index 261d6bb57e6..3f18b264e59 100644
--- a/guix/combinators.scm
+++ b/guix/combinators.scm
@@ -18,6 +18,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provides useful combinators that complement SRFI-1 and
+;;; friends.
+;;;
+;;; Code:
+
 (define-module (guix combinators)
   #:use-module (ice-9 match)
   #:use-module (ice-9 vlist)
@@ -28,13 +35,6 @@
             procedure-call-location
             define-compile-time-procedure))
 
-;;; Commentary:
-;;;
-;;; This module provides useful combinators that complement SRFI-1 and
-;;; friends.
-;;;
-;;; Code:
-
 (define fold2
   (case-lambda
     ((proc seed1 seed2 lst)
diff --git a/guix/config.scm.in b/guix/config.scm.in
index 62e15dd713f..89946ed9e9a 100644
--- a/guix/config.scm.in
+++ b/guix/config.scm.in
@@ -17,6 +17,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Compile-time configuration of Guix.  When adding a substitution variable
+;;; here, make sure to equip (guix scripts pull) to substitute it.
+;;;
+;;; Code:
+
 (define-module (guix config)
   #:export (%guix-package-name
             %guix-version
@@ -40,13 +47,6 @@
             %bzip2
             %xz))
 
-;;; Commentary:
-;;;
-;;; Compile-time configuration of Guix.  When adding a substitution variable
-;;; here, make sure to equip (guix scripts pull) to substitute it.
-;;;
-;;; Code:
-
 (define %guix-package-name
   "@PACKAGE_NAME@")
 
diff --git a/guix/cpio.scm b/guix/cpio.scm
index 876f61ea3c6..6361ea55fc9 100644
--- a/guix/cpio.scm
+++ b/guix/cpio.scm
@@ -17,6 +17,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module implements the cpio "new ASCII" format, bit-for-bit identical
+;;; to GNU cpio with the '-H newc' option.
+;;;
+;;; Code:
+
 (define-module (guix cpio)
   #:use-module ((guix build syscalls) #:select (device-number
                                                 device-number->major+minor))
@@ -36,13 +43,6 @@
 
             write-cpio-archive))
 
-;;; Commentary:
-;;;
-;;; This module implements the cpio "new ASCII" format, bit-for-bit identical
-;;; to GNU cpio with the '-H newc' option.
-;;;
-;;; Code:
-
 ;; Values for 'mode', OR'd together.
 
 (define C_IRUSR #o000400)
diff --git a/guix/cpu.scm b/guix/cpu.scm
index 39766f8e9dc..aad06e46e8b 100644
--- a/guix/cpu.scm
+++ b/guix/cpu.scm
@@ -17,6 +17,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provides tools to determine the micro-architecture supported
+;;; by the CPU and to map it to a name known to GCC's '-march'.
+;;;
+;;; Code:
+
 (define-module (guix cpu)
   #:use-module (guix sets)
   #:use-module (guix memoization)
@@ -35,13 +42,6 @@
             cpu->gcc-architecture
             gcc-architecture->micro-architecture-level))
 
-;;; Commentary:
-;;;
-;;; This module provides tools to determine the micro-architecture supported
-;;; by the CPU and to map it to a name known to GCC's '-march'.
-;;;
-;;; Code:
-
 ;; CPU description.
 (define-record-type <cpu>
   (cpu architecture vendor family model flags)
diff --git a/guix/cve.scm b/guix/cve.scm
index 5c14b068b17..83f137dba36 100644
--- a/guix/cve.scm
+++ b/guix/cve.scm
@@ -17,6 +17,14 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provides the tools to fetch, parse, and digest part of the
+;;; Common Vulnerabilities and Exposures (CVE) feeds provided by the US NIST
+;;; at <https://nvd.nist.gov/vuln/data-feeds>.
+;;;
+;;; Code:
+
 (define-module (guix cve)
   #:use-module (guix utils)
   #:use-module (guix http-client)
@@ -54,14 +62,6 @@
             current-vulnerabilities
             vulnerabilities->lookup-proc))
 
-;;; Commentary:
-;;;
-;;; This module provides the tools to fetch, parse, and digest part of the
-;;; Common Vulnerabilities and Exposures (CVE) feeds provided by the US NIST
-;;; at <https://nvd.nist.gov/vuln/data-feeds>.
-;;;
-;;; Code:
-
 (define (string->date* str)
   (string->date str "~Y-~m-~dT~H:~M:~S"))
 
diff --git a/guix/cvs-download.scm b/guix/cvs-download.scm
index 7d7d741b71c..4957e87557a 100644
--- a/guix/cvs-download.scm
+++ b/guix/cvs-download.scm
@@ -18,6 +18,15 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; An <origin> method that fetches a specific revision or date from a CVS
+;;; repository.  The CVS-ROOT-DIRECTORY, MODULE and REVISION are specified
+;;; with a <cvs-reference> object.  REVISION should be specified as either a
+;;; date string in ISO-8601 format (e.g. "2012-12-21") or a CVS tag.
+;;;
+;;; Code:
+
 (define-module (guix cvs-download)
   #:use-module (guix records)
   #:use-module (guix gexp)
@@ -34,15 +43,6 @@
             cvs-reference-revision
             cvs-fetch))
 
-;;; Commentary:
-;;;
-;;; An <origin> method that fetches a specific revision or date from a CVS
-;;; repository.  The CVS-ROOT-DIRECTORY, MODULE and REVISION are specified
-;;; with a <cvs-reference> object.  REVISION should be specified as either a
-;;; date string in ISO-8601 format (e.g. "2012-12-21") or a CVS tag.
-;;;
-;;; Code:
-
 (define-record-type* <cvs-reference>
   cvs-reference make-cvs-reference
   cvs-reference?
diff --git a/guix/deprecation.scm b/guix/deprecation.scm
index 47e653dfb2d..82be14c8c87 100644
--- a/guix/deprecation.scm
+++ b/guix/deprecation.scm
@@ -17,6 +17,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Provide a mechanism to mark bindings as deprecated.
+;;;
+;;; Code:
+
 (define-module (guix deprecation)
   #:use-module (guix i18n)
   #:use-module (guix diagnostics)
@@ -30,12 +36,6 @@
             warn-about-old-daemon
             warn-about-deprecation))
 
-;;; Commentary:
-;;;
-;;; Provide a mechanism to mark bindings as deprecated.
-;;;
-;;; Code:
-
 (define (warn-about-old-daemon)
   (warning (G_ "Your Guix daemon is severely outdated, and will soon cease to
 be able to download binary substitutes.  To upgrade it, refer to the
diff --git a/guix/describe.scm b/guix/describe.scm
index 120a97ab052..40eb6430443 100644
--- a/guix/describe.scm
+++ b/guix/describe.scm
@@ -16,6 +16,16 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provides supporting code to allow a Guix instance to find, at
+;;; run time, which profile it's in (profiles created by 'guix pull').  That
+;;; allows it to read meta-information about itself (e.g., repository URL and
+;;; commit ID) and to find other channels available in the same profile.  It's
+;;; a bit like ELPA's pkg-info.el.
+;;;
+;;; Code:
+
 (define-module (guix describe)
   #:use-module (guix memoization)
   #:use-module (guix profiles)
@@ -44,16 +54,6 @@
             manifest-entry-with-provenance
             manifest-entry-provenance))
 
-;;; Commentary:
-;;;
-;;; This module provides supporting code to allow a Guix instance to find, at
-;;; run time, which profile it's in (profiles created by 'guix pull').  That
-;;; allows it to read meta-information about itself (e.g., repository URL and
-;;; commit ID) and to find other channels available in the same profile.  It's
-;;; a bit like ELPA's pkg-info.el.
-;;;
-;;; Code:
-
 (define initial-program-arguments
   ;; Save the initial program arguments.  This allows us to see the "real"
   ;; 'guix' program, even if 'guix repl -s' calls 'set-program-arguments'
diff --git a/guix/diagnostics.scm b/guix/diagnostics.scm
index 3f1f527b437..602b9f6c4ee 100644
--- a/guix/diagnostics.scm
+++ b/guix/diagnostics.scm
@@ -16,6 +16,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provides the tools to report diagnostics to the user in a
+;;; consistent way: errors, warnings, and notes.
+;;;
+;;; Code:
+
 (define-module (guix diagnostics)
   #:use-module (guix colors)
   #:use-module (guix i18n)
@@ -60,13 +67,6 @@
 
             define-with-syntax-properties))
 
-;;; Commentary:
-;;;
-;;; This module provides the tools to report diagnostics to the user in a
-;;; consistent way: errors, warnings, and notes.
-;;;
-;;; Code:
-
 (define (trivial-format-string? fmt)
   (define len
     (string-length fmt))
diff --git a/guix/discovery.scm b/guix/discovery.scm
index 2febfcdcb71..5a1847b9440 100644
--- a/guix/discovery.scm
+++ b/guix/discovery.scm
@@ -16,6 +16,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provides tools to discover Guile modules and the variables
+;;; they export.
+;;;
+;;; Code:
+
 (define-module (guix discovery)
   #:use-module (guix i18n)
   #:use-module (guix modules)
@@ -32,13 +39,6 @@
             fold-module-public-variables
             fold-module-public-variables*))
 
-;;; Commentary:
-;;;
-;;; This module provides tools to discover Guile modules and the variables
-;;; they export.
-;;;
-;;; Code:
-
 (define* (scheme-files directory)
   "Return the list of Scheme files found under DIRECTORY, recursively.  The
 returned list is sorted in alphabetical order.  Return the empty list if
diff --git a/guix/download.scm b/guix/download.scm
index 0a34e00a852..d76fe10ace1 100644
--- a/guix/download.scm
+++ b/guix/download.scm
@@ -23,6 +23,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Produce fixed-output derivations with data fetched over HTTP or FTP.
+;;;
+;;; Code:
+
 (define-module (guix download)
   #:use-module (ice-9 match)
   #:use-module (guix derivations)
@@ -44,12 +50,6 @@
             url-fetch/zipbomb
             download-to-store))
 
-;;; Commentary:
-;;;
-;;; Produce fixed-output derivations with data fetched over HTTP or FTP.
-;;;
-;;; Code:
-
 (define %mirrors
   ;; Mirror lists used when `mirror://' URLs are passed.  The first mirror
   ;; entry of each set should ideally be the most authoritative one, as that's
diff --git a/guix/ftp-client.scm b/guix/ftp-client.scm
index 24b18a8033b..37c83bc7db6 100644
--- a/guix/ftp-client.scm
+++ b/guix/ftp-client.scm
@@ -16,6 +16,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Simple FTP client (RFC 959).
+;;;
+;;; Code:
+
 (define-module (guix ftp-client)
   #:use-module (srfi srfi-1)
   #:use-module (srfi srfi-9)
@@ -36,12 +42,6 @@
             ftp-list
             ftp-retr))
 
-;;; Commentary:
-;;;
-;;; Simple FTP client (RFC 959).
-;;;
-;;; Code:
-
 ;; TODO: Use SRFI-3{4,5} error conditions.
 
 (define-record-type <ftp-connection>
diff --git a/guix/gexp.scm b/guix/gexp.scm
index 02b05fb95eb..c53c7f0f38a 100644
--- a/guix/gexp.scm
+++ b/guix/gexp.scm
@@ -23,6 +23,23 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module implements "G-expressions", or "gexps".  Gexps are like
+;;; S-expressions (sexps), with two differences:
+;;;
+;;;   1. References (un-quotations) to derivations or packages in a gexp are
+;;;      replaced by the corresponding output file name; in addition, the
+;;;      'ungexp-native' unquote-like form allows code to explicitly refer to
+;;;      the native code of a given package, in case of cross-compilation;
+;;;
+;;;   2. Gexps embed information about the derivations they refer to.
+;;;
+;;; Gexps make it easy to write to files Scheme code that refers to store
+;;; items, or to write Scheme code to build derivations.
+;;;
+;;; Code:
+
 (define-module (guix gexp)
   #:use-module (guix store)
   #:use-module (guix monads)
@@ -142,23 +159,6 @@
             gexp-input-error?
             gexp-error-invalid-input))
 
-;;; Commentary:
-;;;
-;;; This module implements "G-expressions", or "gexps".  Gexps are like
-;;; S-expressions (sexps), with two differences:
-;;;
-;;;   1. References (un-quotations) to derivations or packages in a gexp are
-;;;      replaced by the corresponding output file name; in addition, the
-;;;      'ungexp-native' unquote-like form allows code to explicitly refer to
-;;;      the native code of a given package, in case of cross-compilation;
-;;;
-;;;   2. Gexps embed information about the derivations they refer to.
-;;;
-;;; Gexps make it easy to write to files Scheme code that refers to store
-;;; items, or to write Scheme code to build derivations.
-;;;
-;;; Code:
-
 ;; "G expressions".
 (define-record-type <gexp>
   (make-gexp references modules extensions proc location)
diff --git a/guix/git-authenticate.scm b/guix/git-authenticate.scm
index 5cf92b422ac..c7a26217236 100644
--- a/guix/git-authenticate.scm
+++ b/guix/git-authenticate.scm
@@ -17,6 +17,15 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provides tools to authenticate a range of Git commits.  A
+;;; commit is considered "authentic" if and only if it is signed by an
+;;; authorized party.  Parties authorized to sign a commit are listed in the
+;;; '.guix-authorizations' file of the parent commit.
+;;;
+;;; Code:
+
 (define-module (guix git-authenticate)
   #:autoload   (git oid) (oid->string
                           string->oid)
@@ -81,15 +90,6 @@
             missing-key-error?
             missing-key-error-signature))
 
-;;; Commentary:
-;;;
-;;; This module provides tools to authenticate a range of Git commits.  A
-;;; commit is considered "authentic" if and only if it is signed by an
-;;; authorized party.  Parties authorized to sign a commit are listed in the
-;;; '.guix-authorizations' file of the parent commit.
-;;;
-;;; Code:
-
 (define-condition-type &git-authentication-error &error
   git-authentication-error?
   (commit  git-authentication-error-commit))
diff --git a/guix/git-download.scm b/guix/git-download.scm
index 609382eba11..a636a36bb47 100644
--- a/guix/git-download.scm
+++ b/guix/git-download.scm
@@ -21,6 +21,14 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; An <origin> method that fetches a specific commit from a Git repository.
+;;; The repository URL and commit hash are specified with a <git-reference>
+;;; object.
+;;;
+;;; Code:
+
 (define-module (guix git-download)
   #:use-module (guix gexp)
   #:use-module (guix store)
@@ -61,14 +69,6 @@
             git-file-name
             git-predicate))
 
-;;; Commentary:
-;;;
-;;; An <origin> method that fetches a specific commit from a Git repository.
-;;; The repository URL and commit hash are specified with a <git-reference>
-;;; object.
-;;;
-;;; Code:
-
 (define-record-type* <git-reference>
   git-reference make-git-reference
   git-reference?
diff --git a/guix/glob.scm b/guix/glob.scm
index 13fa99f511d..fbd6eda65ce 100644
--- a/guix/glob.scm
+++ b/guix/glob.scm
@@ -17,13 +17,6 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
-(define-module (guix glob)
-  #:use-module (ice-9 match)
-  #:export (string->sglob
-            compile-sglob
-            string->compiled-sglob
-            glob-match?))
-
 ;;; Commentary:
 ;;;
 ;;; This is a minimal implementation of "glob patterns" (info "(libc)
@@ -32,6 +25,13 @@
 ;;;
 ;;; Code:
 
+(define-module (guix glob)
+  #:use-module (ice-9 match)
+  #:export (string->sglob
+            compile-sglob
+            string->compiled-sglob
+            glob-match?))
+
 (define (parse-bracket chars)
   "Parse CHARS, a list of characters that extracted from a '[...]' sequence."
   (match chars
diff --git a/guix/gnu-maintenance.scm b/guix/gnu-maintenance.scm
index 95594bc839f..1e76d0dfdb5 100644
--- a/guix/gnu-maintenance.scm
+++ b/guix/gnu-maintenance.scm
@@ -20,6 +20,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Code for dealing with the maintenance of GNU packages, such as
+;;; auto-updates.
+;;;
+;;; Code:
+
 (define-module (guix gnu-maintenance)
   #:use-module (web uri)
   #:use-module (web client)
@@ -82,13 +89,6 @@
             %kernel.org-updater
             %generic-html-updater))
 
-;;; Commentary:
-;;;
-;;; Code for dealing with the maintenance of GNU packages, such as
-;;; auto-updates.
-;;;
-;;; Code:
-
 
 ;;;
 ;;; List of GNU packages.
diff --git a/guix/gnupg.scm b/guix/gnupg.scm
index 498f8b34a92..03ba6d5c6e0 100644
--- a/guix/gnupg.scm
+++ b/guix/gnupg.scm
@@ -19,6 +19,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; GnuPG interface.
+;;;
+;;; Code:
+
 (define-module (guix gnupg)
   #:use-module (ice-9 popen)
   #:use-module (ice-9 match)
@@ -39,12 +45,6 @@
             gnupg-status-good-signature?
             gnupg-status-missing-key?))
 
-;;; Commentary:
-;;;
-;;; GnuPG interface.
-;;;
-;;; Code:
-
 (define %gpg-command
   ;; The GnuPG 2.x command-line program name.
   (make-parameter (or (getenv "GUIX_GPG_COMMAND") "gpg")))
diff --git a/guix/graph.scm b/guix/graph.scm
index 208560bd6a8..97ac950a406 100644
--- a/guix/graph.scm
+++ b/guix/graph.scm
@@ -17,6 +17,16 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provides an abstract way to represent graphs and to manipulate
+;;; them.  It comes with several such representations for packages,
+;;; derivations, and store items.  It also provides a generic interface for
+;;; exporting graphs in an external format, including a Graphviz
+;;; implementation thereof.
+;;;
+;;; Code:
+
 (define-module (guix graph)
   #:use-module (guix store)
   #:use-module (guix monads)
@@ -61,16 +71,6 @@
 
             export-graph))
 
-;;; Commentary:
-;;;
-;;; This module provides an abstract way to represent graphs and to manipulate
-;;; them.  It comes with several such representations for packages,
-;;; derivations, and store items.  It also provides a generic interface for
-;;; exporting graphs in an external format, including a Graphviz
-;;; implementation thereof.
-;;;
-;;; Code:
-
 
 ;;;
 ;;; Node types.
diff --git a/guix/hg-download.scm b/guix/hg-download.scm
index ce13a158c04..f661cba223f 100644
--- a/guix/hg-download.scm
+++ b/guix/hg-download.scm
@@ -18,6 +18,14 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; An <origin> method that fetches a specific changeset from a Mercurial
+;;; repository.  The repository URL and changeset ID are specified with a
+;;; <hg-reference> object.
+;;;
+;;; Code:
+
 (define-module (guix hg-download)
   #:use-module (guix gexp)
   #:use-module (guix store)
@@ -40,14 +48,6 @@
             hg-version
             hg-file-name))
 
-;;; Commentary:
-;;;
-;;; An <origin> method that fetches a specific changeset from a Mercurial
-;;; repository.  The repository URL and changeset ID are specified with a
-;;; <hg-reference> object.
-;;;
-;;; Code:
-
 (define-record-type* <hg-reference>
   hg-reference make-hg-reference
   hg-reference?
diff --git a/guix/http-client.scm b/guix/http-client.scm
index 0656a8a563d..7660a90eadc 100644
--- a/guix/http-client.scm
+++ b/guix/http-client.scm
@@ -19,6 +19,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; HTTP client portable among Guile versions, and with proper error condition
+;;; reporting.
+;;;
+;;; Code:
+
 (define-module (guix http-client)
   #:use-module (web uri)
   #:use-module (web http)
@@ -65,13 +72,6 @@
             %http-cache-ttl
             http-fetch/cached))
 
-;;; Commentary:
-;;;
-;;; HTTP client portable among Guile versions, and with proper error condition
-;;; reporting.
-;;;
-;;; Code:
-
 ;; HTTP GET error.
 (define-condition-type &http-get-error &error
   http-get-error?
diff --git a/guix/i18n.scm b/guix/i18n.scm
index f81e6b38ece..c5974ea4cb8 100644
--- a/guix/i18n.scm
+++ b/guix/i18n.scm
@@ -16,6 +16,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Internationalization support.
+;;;
+;;; Code:
+
 (define-module (guix i18n)
   #:use-module (srfi srfi-26)
   #:export (G_
@@ -24,12 +30,6 @@
             %gettext-domain
             %package-text-domain))
 
-;;; Commentary:
-;;;
-;;; Internationalization support.
-;;;
-;;; Code:
-
 (define %gettext-domain
   ;; Text domain for strings used in the tools.
   "guix")
diff --git a/guix/import/apache.scm b/guix/import/apache.scm
index c17139cc39e..095d7284b22 100644
--- a/guix/import/apache.scm
+++ b/guix/import/apache.scm
@@ -19,6 +19,14 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This package provides not an actual importer but simply an updater for
+;;; ASF packages.  It grabs available files from the 'find-ls2.txt.gz' file
+;;; available on dlcdn.apache.org.
+;;;
+;;; Code:
+
 (define-module (guix import apache)
   #:use-module ((guix import utils) #:select (find-version))
   #:use-module (guix http-client)
@@ -35,14 +43,6 @@
 
   #:export (%apache-updater))
 
-;;; Commentary:
-;;;
-;;; This package provides not an actual importer but simply an updater for
-;;; ASF packages.  It grabs available files from the 'find-ls2.txt.gz' file
-;;; available on dlcdn.apache.org.
-;;;
-;;; Code:
-
 (define (tarball->version tarball)
   "Return the version TARBALL corresponds to.  TARBALL is a file name like
 \"coreutils-8.23.tar.xz\"."
diff --git a/guix/import/cpan.scm b/guix/import/cpan.scm
index 3d4508b11e6..0bfe4ed35f0 100644
--- a/guix/import/cpan.scm
+++ b/guix/import/cpan.scm
@@ -21,6 +21,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Generate a package declaration template for the latest version of a CPAN
+;;; module, using meta-data from metacpan.org.
+;;;
+;;; Code:
+
 (define-module (guix import cpan)
   #:use-module (ice-9 match)
   #:use-module (ice-9 regex)
@@ -48,13 +55,6 @@
 
             %metacpan-base-url))
 
-;;; Commentary:
-;;;
-;;; Generate a package declaration template for the latest version of a CPAN
-;;; module, using meta-data from metacpan.org.
-;;;
-;;; Code:
-
 (define %metacpan-base-url
   ;; Base URL of the MetaCPAN API.
   (make-parameter "https://fastapi.metacpan.org/v1/"))
diff --git a/guix/import/cran.scm b/guix/import/cran.scm
index 6681380c474..f49b3586dd8 100644
--- a/guix/import/cran.scm
+++ b/guix/import/cran.scm
@@ -23,6 +23,14 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Generate a package declaration template for the latest version of an R
+;;; package on CRAN, using the DESCRIPTION file downloaded from
+;;; cran.r-project.org.
+;;;
+;;; Code:
+
 (define-module (guix import cran)
   #:use-module (ice-9 ftw)
   #:use-module (ice-9 match)
@@ -78,14 +86,6 @@
             description->alist
             description->package))
 
-;;; Commentary:
-;;;
-;;; Generate a package declaration template for the latest version of an R
-;;; package on CRAN, using the DESCRIPTION file downloaded from
-;;; cran.r-project.org.
-;;;
-;;; Code:
-
 (define %input-style
   (make-parameter 'variable)) ; or 'specification
 
diff --git a/guix/import/egg.scm b/guix/import/egg.scm
index c9606ff8391..b1dc52cfa8c 100644
--- a/guix/import/egg.scm
+++ b/guix/import/egg.scm
@@ -21,29 +21,6 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
-(define-module (guix import egg)
-  #:use-module (ice-9 ftw)
-  #:use-module (ice-9 match)
-  #:use-module (srfi srfi-1)
-  #:use-module (srfi srfi-26)
-  #:use-module (srfi srfi-71)
-  #:use-module (gcrypt hash)
-  #:use-module (guix git)
-  #:use-module (guix base32)
-  #:use-module (guix memoization)
-  #:use-module (guix packages)
-  #:use-module (guix upstream)
-  #:use-module (guix build-system chicken)
-  #:use-module (guix store)
-  #:use-module ((guix download) #:select (download-to-store url-fetch))
-  #:use-module (guix import utils)
-  #:export (egg->guix-package
-            egg-recursive-import
-            %egg-updater
-
-            ;; For tests.
-            guix-package->egg-name))
-
 ;;; Commentary:
 ;;;
 ;;; (guix import egg) provides package importer for CHICKEN eggs.  See the
@@ -72,6 +49,29 @@
 ;;;
 ;;; Code:
 
+(define-module (guix import egg)
+  #:use-module (ice-9 ftw)
+  #:use-module (ice-9 match)
+  #:use-module (srfi srfi-1)
+  #:use-module (srfi srfi-26)
+  #:use-module (srfi srfi-71)
+  #:use-module (gcrypt hash)
+  #:use-module (guix git)
+  #:use-module (guix base32)
+  #:use-module (guix memoization)
+  #:use-module (guix packages)
+  #:use-module (guix upstream)
+  #:use-module (guix build-system chicken)
+  #:use-module (guix store)
+  #:use-module ((guix download) #:select (download-to-store url-fetch))
+  #:use-module (guix import utils)
+  #:export (egg->guix-package
+            egg-recursive-import
+            %egg-updater
+
+            ;; For tests.
+            guix-package->egg-name))
+
 
 ;;;
 ;;; Egg metadata fetcher and helper functions.
diff --git a/guix/import/git.scm b/guix/import/git.scm
index e6dab7f25fa..4000c349bee 100644
--- a/guix/import/git.scm
+++ b/guix/import/git.scm
@@ -19,24 +19,6 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
-(define-module (guix import git)
-  #:use-module (guix i18n)
-  #:use-module (guix diagnostics)
-  #:use-module (guix git)
-  #:use-module (guix git-download)
-  #:use-module (guix packages)
-  #:use-module (guix upstream)
-  #:use-module ((guix import utils) #:select (find-version))
-  #:use-module (ice-9 match)
-  #:use-module (ice-9 regex)
-  #:use-module (srfi srfi-1)
-  #:use-module (srfi srfi-26)
-  #:use-module (srfi srfi-34)
-  #:use-module (srfi srfi-35)
-  #:use-module (srfi srfi-71)
-  #:export (%generic-git-updater
-            get-tags))
-
 ;;; Commentary:
 ;;;
 ;;; This module provides a generic package updater for packages hosted on Git
@@ -57,6 +39,24 @@
 ;;;
 ;;; Code:
 
+(define-module (guix import git)
+  #:use-module (guix i18n)
+  #:use-module (guix diagnostics)
+  #:use-module (guix git)
+  #:use-module (guix git-download)
+  #:use-module (guix packages)
+  #:use-module (guix upstream)
+  #:use-module ((guix import utils) #:select (find-version))
+  #:use-module (ice-9 match)
+  #:use-module (ice-9 regex)
+  #:use-module (srfi srfi-1)
+  #:use-module (srfi srfi-26)
+  #:use-module (srfi srfi-34)
+  #:use-module (srfi srfi-35)
+  #:use-module (srfi srfi-71)
+  #:export (%generic-git-updater
+            get-tags))
+
 ;;; Errors & warnings
 
 (define-condition-type &git-no-valid-tags-error &error
diff --git a/guix/import/gnome.scm b/guix/import/gnome.scm
index 211352ac3aa..2db80986291 100644
--- a/guix/import/gnome.scm
+++ b/guix/import/gnome.scm
@@ -18,6 +18,14 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This package provides not an actual importer but simply an updater for
+;;; GNOME packages.  It grabs package meta-data from 'cache.json' files
+;;; available on ftp.gnome.org.
+;;;
+;;; Code:
+
 (define-module (guix import gnome)
   #:use-module ((guix import utils) #:select (find-version))
   #:use-module (guix upstream)
@@ -34,14 +42,6 @@
   #:use-module (ice-9 regex)
   #:export (%gnome-updater))
 
-;;; Commentary:
-;;;
-;;; This package provides not an actual importer but simply an updater for
-;;; GNOME packages.  It grabs package meta-data from 'cache.json' files
-;;; available on ftp.gnome.org.
-;;;
-;;; Code:
-
 (define (jsonish->upstream-source name jsonish)
   "Return an <upstream-source> object for package NAME, using JSONISH as the
 source for metadata."
diff --git a/guix/import/gnu.scm b/guix/import/gnu.scm
index ee7f2f61b98..c373fd2eb19 100644
--- a/guix/import/gnu.scm
+++ b/guix/import/gnu.scm
@@ -18,6 +18,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Generate a package declaration template for the latest version of a GNU
+;;; package, using meta-data available upstream for the package.
+;;;
+;;; Code:
+
 (define-module (guix import gnu)
   #:use-module ((guix diagnostics) #:select (formatted-message))
   #:use-module (guix gnu-maintenance)
@@ -33,13 +40,6 @@
   #:use-module (ice-9 match)
   #:export (gnu->guix-package))
 
-;;; Commentary:
-;;;
-;;; Generate a package declaration template for the latest version of a GNU
-;;; package, using meta-data available upstream for the package.
-;;;
-;;; Code:
-
 (define (qualified-url url)
   "Return a fully-qualified URL based on URL."
   (if (string-prefix? "/" url)
diff --git a/guix/import/go.scm b/guix/import/go.scm
index 0e65994d0ea..3a75f8e60c5 100644
--- a/guix/import/go.scm
+++ b/guix/import/go.scm
@@ -26,6 +26,41 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; (guix import go) attempts to make it easier to create Guix package
+;;; declarations for Go modules.
+;;;
+;;; Modules in Go are a "collection of related Go packages" which are "the
+;;; unit of source code interchange and versioning".  Modules are generally
+;;; hosted in a repository.
+;;;
+;;; Monorepo is a collection of modules within the same VCS source.  Each
+;;; module of monorepo may be released individually by assigning
+;;; "<subdir>/v<semver>" tag (see: https://go.dev/ref/mod#modules-overview).
+;;;
+;;; At this point it should handle correctly modules which have only Go
+;;; dependencies and are accessible from proxy.golang.org (or configured via
+;;; GOPROXY).
+;;;
+;;; We want it to work more or less this way:
+;;; - get latest version for the module from GOPROXY
+;;; - infer VCS root repo from which we will check-out source by
+;;;   + recognising known patterns (like github.com)
+;;;   + or recognizing .vcs suffix
+;;;   + or parsing meta tag in HTML served at the URL
+;;;   + or (TODO) if nothing else works by using zip file served by GOPROXY
+;;; - get go.mod from GOPROXY (which is able to synthesize one if needed)
+;;; - extract list of dependencies from this go.mod
+;;;
+;;; The Go module paths are translated to a Guix package name under the
+;;; assumption that there will be no collision.
+;;;
+;;; TODO list
+;;; - get correct hash in vcs->origin for Mercurial and Subversion
+;;;
+;;; Code:
+
 (define-module (guix import go)
   #:use-module (guix build-system go)
   #:use-module (guix git)
@@ -38,7 +73,7 @@
   #:use-module (guix packages)
   #:use-module (guix http-client)
   #:use-module (guix memoization)
-  #:autoload   (htmlprag) (html->sxml)            ;from Guile-Lib
+  #:autoload   (htmlprag) (html->sxml)  ;from Guile-Lib
   #:autoload   (guix ui) (warning)
   #:autoload   (git structs) (git-error-message)
   #:use-module (ice-9 format)
@@ -64,41 +99,6 @@
             go-module->guix-package*
             go-module-recursive-import))
 
-;;; Commentary:
-;;;
-;;; (guix import go) attempts to make it easier to create Guix package
-;;; declarations for Go modules.
-;;;
-;;; Modules in Go are a "collection of related Go packages" which are "the
-;;; unit of source code interchange and versioning".  Modules are generally
-;;; hosted in a repository.
-;;;
-;;; Monorepo is a collection of modules within the same VCS source.  Each
-;;; module of monorepo may be released individually by assigning
-;;; "<subdir>/v<semver>" tag (see: https://go.dev/ref/mod#modules-overview).
-;;;
-;;; At this point it should handle correctly modules which have only Go
-;;; dependencies and are accessible from proxy.golang.org (or configured via
-;;; GOPROXY).
-;;;
-;;; We want it to work more or less this way:
-;;; - get latest version for the module from GOPROXY
-;;; - infer VCS root repo from which we will check-out source by
-;;;   + recognising known patterns (like github.com)
-;;;   + or recognizing .vcs suffix
-;;;   + or parsing meta tag in HTML served at the URL
-;;;   + or (TODO) if nothing else works by using zip file served by GOPROXY
-;;; - get go.mod from GOPROXY (which is able to synthesize one if needed)
-;;; - extract list of dependencies from this go.mod
-;;;
-;;; The Go module paths are translated to a Guix package name under the
-;;; assumption that there will be no collision.
-
-;;; TODO list
-;;; - get correct hash in vcs->origin for Mercurial and Subversion
-
-;;; Code:
-
 (define (go-package)
   "Return the 'go' package.  This is a lazy reference so that we don't
 depend on (gnu packages golang)."
diff --git a/guix/import/kde.scm b/guix/import/kde.scm
index 64e2182e879..d7a3e378425 100644
--- a/guix/import/kde.scm
+++ b/guix/import/kde.scm
@@ -19,6 +19,14 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This package provides not an actual importer but simply an updater for
+;;; KDE packages.  It grabs available files from the 'ls-lR.bz2' file
+;;; available on download.kde.org.
+;;;
+;;; Code:
+
 (define-module (guix import kde)
   #:use-module ((guix import utils) #:select (find-version))
   #:use-module (guix http-client)
@@ -35,14 +43,6 @@
 
   #:export (%kde-updater))
 
-;;; Commentary:
-;;;
-;;; This package provides not an actual importer but simply an updater for
-;;; KDE packages.  It grabs available files from the 'ls-lR.bz2' file
-;;; available on download.kde.org.
-;;;
-;;; Code:
-
 (define (tarball->version tarball)
   "Return the version TARBALL corresponds to.  TARBALL is a file name like
 \"coreutils-8.23.tar.xz\"."
diff --git a/guix/import/test.scm b/guix/import/test.scm
index 7414cf5253f..997b4fd5ab8 100644
--- a/guix/import/test.scm
+++ b/guix/import/test.scm
@@ -16,6 +16,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module defines a pseudo updater whose sole purpose is to allow
+;;; testing of the whole 'guix refresh' command.
+;;;
+;;; Code:
+
 (define-module (guix import test)
   #:use-module (srfi srfi-1)
   #:use-module (srfi srfi-26)
@@ -27,13 +34,6 @@
   #:use-module (ice-9 match)
   #:export (%test-updater))
 
-;;; Commentary:
-;;;
-;;; This module defines a pseudo updater whose sole purpose is to allow
-;;; testing of the whole 'guix refresh' command.
-;;;
-;;; Code:
-
 (define test-target-version
   ;; VHash that maps package names to version/URL tuples.
   (make-parameter
diff --git a/guix/import/texlive.scm b/guix/import/texlive.scm
index 2b36251f44c..23ec3c00fda 100644
--- a/guix/import/texlive.scm
+++ b/guix/import/texlive.scm
@@ -18,6 +18,14 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Generate a package declaration template for corresponding package in the
+;;; Tex Live Package Database (tlpdb).  We fetch all sources from different
+;;; locations in the SVN repository of the Texlive project.
+;;;
+;;; Code:
+
 (define-module (guix import texlive)
   #:use-module (gcrypt hash)
   #:use-module (guix base32)
@@ -51,14 +59,6 @@
             texlive-recursive-import
             %texlive-updater))
 
-;;; Commentary:
-;;;
-;;; Generate a package declaration template for corresponding package in the
-;;; Tex Live Package Database (tlpdb).  We fetch all sources from different
-;;; locations in the SVN repository of the Texlive project.
-;;;
-;;; Code:
-
 ;; Generic locations are parts of the tree shared by multiple packages.
 ;; Package definitions should single out files stored there, or all files in
 ;; the directory from all involved packages would be downloaded.
diff --git a/guix/inferior.scm b/guix/inferior.scm
index 57490afc484..2a490ae6320 100644
--- a/guix/inferior.scm
+++ b/guix/inferior.scm
@@ -16,6 +16,14 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provides a way to spawn Guix "inferior" processes and to talk
+;;; to them.  It allows us, from one instance of Guix, to interact with
+;;; another instance of Guix coming from a different commit.
+;;;
+;;; Code:
+
 (define-module (guix inferior)
   #:use-module (srfi srfi-9)
   #:use-module (srfi srfi-9 gnu)
@@ -103,14 +111,6 @@
             cached-channel-instance
             inferior-for-channels))
 
-;;; Commentary:
-;;;
-;;; This module provides a way to spawn Guix "inferior" processes and to talk
-;;; to them.  It allows us, from one instance of Guix, to interact with
-;;; another instance of Guix coming from a different commit.
-;;;
-;;; Code:
-
 ;; Inferior Guix process.
 (define-record-type <inferior>
   (inferior pid socket close version packages table
diff --git a/guix/ipfs.scm b/guix/ipfs.scm
index 3c25f2a4991..669943df842 100644
--- a/guix/ipfs.scm
+++ b/guix/ipfs.scm
@@ -16,6 +16,14 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module implements bindings for the HTTP interface of the IPFS
+;;; gateway, documented here: <https://docs.ipfs.io/reference/api/http/>.  It
+;;; allows you to add and retrieve files over IPFS, and a few other things.
+;;;
+;;; Code:
+
 (define-module (guix ipfs)
   #:use-module (json)
   #:use-module (srfi srfi-1)
@@ -39,14 +47,6 @@
             read-contents
             publish-name))
 
-;;; Commentary:
-;;;
-;;; This module implements bindings for the HTTP interface of the IPFS
-;;; gateway, documented here: <https://docs.ipfs.io/reference/api/http/>.  It
-;;; allows you to add and retrieve files over IPFS, and a few other things.
-;;;
-;;; Code:
-
 (define %ipfs-base-url
   ;; URL of the IPFS gateway.
   (make-parameter "http://localhost:5001"))
diff --git a/guix/least-authority.scm b/guix/least-authority.scm
index 68dc7e68e8c..62ab632d1b1 100644
--- a/guix/least-authority.scm
+++ b/guix/least-authority.scm
@@ -16,6 +16,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provides tools to execute programs with the least authority
+;;; necessary, using Linux namespaces.
+;;;
+;;; Code:
+
 (define-module (guix least-authority)
   #:use-module (guix gexp)
   #:use-module (guix modules)
@@ -29,13 +36,6 @@
   #:export (least-authority-wrapper
             %default-preserved-environment-variables))
 
-;;; Commentary:
-;;;
-;;; This module provides tools to execute programs with the least authority
-;;; necessary, using Linux namespaces.
-;;;
-;;; Code:
-
 (define %default-preserved-environment-variables
   ;; Environment variables preserved by the wrapper by default.
   '("HOME" "USER" "LOGNAME" "DISPLAY" "XAUTHORITY" "TERM" "TZ" "PAGER"
diff --git a/guix/licenses.scm b/guix/licenses.scm
index bccfbbedee1..24b86adabea 100644
--- a/guix/licenses.scm
+++ b/guix/licenses.scm
@@ -37,6 +37,19 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Available licenses.
+;;;
+;;; This list is based on these links:
+;;; https://github.com/NixOS/nixpkgs/blob/master/lib/licenses.nix
+;;; https://www.gnu.org/licenses/license-list
+;;;
+;;; Please update spdx-string->license from guix/import/utils.scm
+;;; when modifying this list to avoid mismatches.
+;;;
+;;; Code:
+
 (define-module (guix licenses)
   #:use-module (srfi srfi-9)
   #:export (license license? license-name license-uri license-comment
@@ -118,19 +131,6 @@
             hpnd
             fsdg-compatible))
 
-;;; Commentary:
-;;;
-;;; Available licenses.
-;;;
-;;; This list is based on these links:
-;;; https://github.com/NixOS/nixpkgs/blob/master/lib/licenses.nix
-;;; https://www.gnu.org/licenses/license-list
-;;;
-;;; Please update spdx-string->license from guix/import/utils.scm
-;;; when modifying this list to avoid mismatches.
-;;;
-;;; Code:
-
 (define-record-type <license>
   (license name uri comment)
   actual-license?
diff --git a/guix/man-db.scm b/guix/man-db.scm
index d6241480f7e..94798a40db9 100644
--- a/guix/man-db.scm
+++ b/guix/man-db.scm
@@ -17,6 +17,16 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Scan gzipped man pages and create a man-db database.  The database is
+;;; meant to be used by 'man -k KEYWORD'.
+;;;
+;;; The implementation here aims to be simpler than that of 'man-db', and to
+;;; produce deterministic output.  See <https://bugs.gnu.org/29654>.
+;;;
+;;; Code:
+
 (define-module (guix man-db)
   #:autoload (zlib) (call-with-gzip-input-port)
   #:autoload (zstd) (call-with-zstd-input-port)
@@ -37,16 +47,6 @@
             mandb-entries
             write-mandb-database))
 
-;;; Comment:
-;;;
-;;; Scan gzipped man pages and create a man-db database.  The database is
-;;; meant to be used by 'man -k KEYWORD'.
-;;;
-;;; The implementation here aims to be simpler than that of 'man-db', and to
-;;; produce deterministic output.  See <https://bugs.gnu.org/29654>.
-;;;
-;;; Code:
-
 (define-record-type <mandb-entry>
   (mandb-entry file-name name section synopsis kind)
   mandb-entry?
diff --git a/guix/modules.scm b/guix/modules.scm
index 74400ffacc8..e60c18603a0 100644
--- a/guix/modules.scm
+++ b/guix/modules.scm
@@ -16,6 +16,16 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provides introspection tools for Guile modules at the source
+;;; level.  Namely, it allows you to determine the closure of a module; it
+;;; does so just by reading the 'define-module' clause of the module and its
+;;; dependencies.  This is primarily useful as an argument to
+;;; 'with-imported-modules'.
+;;;
+;;; Code:
+
 (define-module (guix modules)
   #:use-module (guix memoization)
   #:use-module (guix sets)
@@ -35,16 +45,6 @@
             live-module-closure
             guix-module-name?))
 
-;;; Commentary:
-;;;
-;;; This module provides introspection tools for Guile modules at the source
-;;; level.  Namely, it allows you to determine the closure of a module; it
-;;; does so just by reading the 'define-module' clause of the module and its
-;;; dependencies.  This is primarily useful as an argument to
-;;; 'with-imported-modules'.
-;;;
-;;; Code:
-
 ;; The error corresponding to a missing module.
 (define-condition-type &missing-dependency-error &error
   missing-dependency-error?
diff --git a/guix/monad-repl.scm b/guix/monad-repl.scm
index fc9654ce9ed..6d8cb1c8b8d 100644
--- a/guix/monad-repl.scm
+++ b/guix/monad-repl.scm
@@ -17,6 +17,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This modules provides a couple of REPL meta-commands that make it easier
+;;; to work with monadic procedures in the store monad.
+;;;
+;;; Code:
+
 (define-module (guix monad-repl)
   #:use-module (guix store)
   #:use-module (guix monads)
@@ -40,13 +47,6 @@
   #:export (run-in-store
             enter-store-monad))
 
-;;; Comment:
-;;;
-;;; This modules provides a couple of REPL meta-commands that make it easier
-;;; to work with monadic procedures in the store monad.
-;;;
-;;; Code:
-
 (define* (monad-language monad run #:optional (name 'monad))
   "Return a language with a special evaluator that causes monadic values
  to be \"run\" in MONAD using procedure RUN."
diff --git a/guix/monads.scm b/guix/monads.scm
index e1b056dc95f..5af7ca67f2d 100644
--- a/guix/monads.scm
+++ b/guix/monads.scm
@@ -17,6 +17,18 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module implements the general mechanism of monads, and provides in
+;;; particular an instance of the "state" monad.  The API was inspired by that
+;;; of Racket's "better-monads" module (see
+;;; <http://planet.racket-lang.org/package-source/toups/functional.plt/1/1/planet-docs/better-monads-guide/index.html>).
+;;; The implementation and use case were influenced by Oleg Kysielov's
+;;; "Monadic Programming in Scheme" (see
+;;; <http://okmij.org/ftp/Scheme/monad-in-Scheme.html>).
+;;;
+;;; Code:
+
 (define-module (guix monads)
   #:use-module ((system syntax)
                 #:select (syntax-local-binding))
@@ -63,18 +75,6 @@
             state-parameterize
             mparameterize))
 
-;;; Commentary:
-;;;
-;;; This module implements the general mechanism of monads, and provides in
-;;; particular an instance of the "state" monad.  The API was inspired by that
-;;; of Racket's "better-monads" module (see
-;;; <http://planet.racket-lang.org/package-source/toups/functional.plt/1/1/planet-docs/better-monads-guide/index.html>).
-;;; The implementation and use case were influenced by Oleg Kysielov's
-;;; "Monadic Programming in Scheme" (see
-;;; <http://okmij.org/ftp/Scheme/monad-in-Scheme.html>).
-;;;
-;;; Code:
-
 ;; Record type for monads manipulated at run time.
 (define-record-type <monad>
   (make-monad bind return)
diff --git a/guix/nar.scm b/guix/nar.scm
index c7842399dcd..fb71e846e83 100644
--- a/guix/nar.scm
+++ b/guix/nar.scm
@@ -17,6 +17,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Read and write Nix archives, aka. ‘nar’.
+;;;
+;;; Code:
+
 (define-module (guix nar)
   #:use-module (guix serialization)
   #:autoload   (guix build syscalls) (lock-file unlock-file)
@@ -48,12 +54,6 @@
 
             restore-file-set))
 
-;;; Comment:
-;;;
-;;; Read and write Nix archives, aka. ‘nar’.
-;;;
-;;; Code:
-
 (define-condition-type &nar-signature-error &nar-error
   nar-signature-error?
   (signature nar-signature-error-signature))      ; faulty signature or #f
diff --git a/guix/openpgp.scm b/guix/openpgp.scm
index d99624911b6..ee1c196eb10 100644
--- a/guix/openpgp.scm
+++ b/guix/openpgp.scm
@@ -25,6 +25,20 @@
 ;;; Ludovic Courtès for use in GNU Guix: turned into a native Guile module,
 ;;; ported to Guile-Gcrypt, and extended and simplified in other ways.
 
+;;; Commentary:
+;;;
+;;; This module contains code to read OpenPGP messages as described in
+;;; <https://tools.ietf.org/html/rfc4880>, with extensions from
+;;; <https://tools.ietf.org/html/draft-ietf-openpgp-rfc4880bis-06> (notably
+;;; EdDSA support and extra signature sub-packets).
+;;;
+;;; Currently this module does enough to verify detached signatures of binary
+;;; data.  It does _not_ perform sanity checks on self-signatures, subkey
+;;; binding signatures, etc., among others.  Use only in a context where this
+;;; limitations are acceptable!
+;;;
+;;; Code:
+
 (define-module (guix openpgp)
   #:export (get-openpgp-detached-signature/ascii
             (get-packet . get-openpgp-packet)
@@ -85,20 +99,6 @@
   #:use-module (gcrypt base16)
   #:use-module ((guix build utils) #:select (dump-port)))
 
-;;; Commentary:
-;;;
-;;; This module contains code to read OpenPGP messages as described in
-;;; <https://tools.ietf.org/html/rfc4880>, with extensions from
-;;; <https://tools.ietf.org/html/draft-ietf-openpgp-rfc4880bis-06> (notably
-;;; EdDSA support and extra signature sub-packets).
-;;;
-;;; Currently this module does enough to verify detached signatures of binary
-;;; data.  It does _not_ perform sanity checks on self-signatures, subkey
-;;; binding signatures, etc., among others.  Use only in a context where this
-;;; limitations are acceptable!
-;;;
-;;; Code:
-
 (define-syntax print
   (syntax-rules ()
     ;; ((_ args ...) (pk 'openpgp args))
diff --git a/guix/packages.scm b/guix/packages.scm
index 5f656e6441d..e43ab37f1f4 100644
--- a/guix/packages.scm
+++ b/guix/packages.scm
@@ -28,6 +28,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provides a high-level mechanism to define packages in a
+;;; Guix-based distribution.
+;;;
+;;; Code:
+
 (define-module (guix packages)
   #:autoload   (guix build utils) (compressor tarball? strip-store-file-name)
   #:use-module (guix utils)
@@ -219,13 +226,6 @@
       (module-re-export! (current-module) '(delete) #:replace? #t)
       (module-re-export! (current-module) '(delete))))
 
-;;; Commentary:
-;;;
-;;; This module provides a high-level mechanism to define packages in a
-;;; Guix-based distribution.
-;;;
-;;; Code:
-
 (define-syntax-rule (define-compile-time-decoder name string->bytevector)
   "Define NAME as a macro that runs STRING->BYTEVECTOR at macro expansion time
 if possible."
diff --git a/guix/pki.scm b/guix/pki.scm
index 91c1be531a9..7b3d1bd0462 100644
--- a/guix/pki.scm
+++ b/guix/pki.scm
@@ -16,6 +16,15 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Public key infrastructure for the authentication and authorization of
+;;; archive imports.  This is essentially a subset of SPKI for our own
+;;; purposes (see <http://theworld.com/~cme/spki.txt> and
+;;; <http://www.ietf.org/rfc/rfc2693.txt>.)
+;;;
+;;; Code:
+
 (define-module (guix pki)
   #:use-module (guix config)
   #:use-module (gcrypt pk-crypto)
@@ -39,15 +48,6 @@
             valid-signature?
             signature-case))
 
-;;; Commentary:
-;;;
-;;; Public key infrastructure for the authentication and authorization of
-;;; archive imports.  This is essentially a subset of SPKI for our own
-;;; purposes (see <http://theworld.com/~cme/spki.txt> and
-;;; <http://www.ietf.org/rfc/rfc2693.txt>.)
-;;;
-;;; Code:
-
 (define (public-keys->acl keys)
   "Return an ACL that lists all of KEYS with a '(guix import)'
 tag---meaning that all of KEYS are authorized for archive imports.  Each
diff --git a/guix/profiles.scm b/guix/profiles.scm
index fb2edbfab34..5e07dc107e1 100644
--- a/guix/profiles.scm
+++ b/guix/profiles.scm
@@ -29,6 +29,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Tools to create and manipulate profiles---i.e., the representation of a
+;;; set of installed packages.
+;;;
+;;; Code:
+
 (define-module (guix profiles)
   #:use-module ((guix config) #:select (%state-directory))
   #:use-module ((guix utils) #:hide (package-name->name+version))
@@ -167,13 +174,6 @@
 
             linux-module-database))
 
-;;; Commentary:
-;;;
-;;; Tools to create and manipulate profiles---i.e., the representation of a
-;;; set of installed packages.
-;;;
-;;; Code:
-
 
 ;;;
 ;;; Condition types.
diff --git a/guix/profiling.scm b/guix/profiling.scm
index e1c205a5438..8c8d5125fff 100644
--- a/guix/profiling.scm
+++ b/guix/profiling.scm
@@ -16,18 +16,18 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
-(define-module (guix profiling)
-  #:use-module (ice-9 match)
-  #:autoload   (ice-9 format) (format)
-  #:export (profiled?
-            register-profiling-hook!))
-
 ;;; Commentary:
 ;;;
 ;;; Basic support for Guix-specific profiling.
 ;;;
 ;;; Code:
 
+(define-module (guix profiling)
+  #:use-module (ice-9 match)
+  #:autoload   (ice-9 format) (format)
+  #:export (profiled?
+            register-profiling-hook!))
+
 (define profiled?
   (let ((profiled
          (or (and=> (getenv "GUIX_PROFILING") string-tokenize)
diff --git a/guix/progress.scm b/guix/progress.scm
index e1b35094e11..98ee3bc3c2f 100644
--- a/guix/progress.scm
+++ b/guix/progress.scm
@@ -19,6 +19,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Helper to write progress report code for downloads, etc.
+;;;
+;;; Code:
+
 (define-module (guix progress)
   #:use-module (guix records)
   #:autoload   (guix build syscalls) (terminal-string-width)
@@ -51,12 +57,6 @@
 
             dump-port*))
 
-;;; Commentary:
-;;;
-;;; Helper to write progress report code for downloads, etc.
-;;;
-;;; Code:
-
 (define-record-type* <progress-reporter>
   progress-reporter make-progress-reporter progress-reporter?
   (start   progress-reporter-start)     ; thunk
diff --git a/guix/quirks.scm b/guix/quirks.scm
index 1cffe971fc7..fe8c001bc4b 100644
--- a/guix/quirks.scm
+++ b/guix/quirks.scm
@@ -16,6 +16,15 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Time traveling is a challenge!  Sometimes, going back to the past requires
+;;; adjusting the old source code so it can be evaluated with our modern day
+;;; Guile and against our modern Guix APIs.  This file describes quirks found
+;;; in old Guix revisions, along with ways to address them or patch them.
+;;;
+;;; Code:
+
 (define-module (guix quirks)
   #:use-module ((guix build utils) #:select (substitute*))
   #:use-module (srfi srfi-9)
@@ -29,15 +38,6 @@
 
             %patches))
 
-;;; Commentary:
-;;;
-;;; Time traveling is a challenge!  Sometimes, going back to the past requires
-;;; adjusting the old source code so it can be evaluated with our modern day
-;;; Guile and against our modern Guix APIs.  This file describes quirks found
-;;; in old Guix revisions, along with ways to address them or patch them.
-;;;
-;;; Code:
-
 (define (syscalls-reexports-local-variables? source)
   "Return true if (guix build syscalls) contains the bug described at
 <https://bugs.gnu.org/36723>."
diff --git a/guix/read-print.scm b/guix/read-print.scm
index 9b3a98c8ee3..6c57f0e94b7 100644
--- a/guix/read-print.scm
+++ b/guix/read-print.scm
@@ -16,6 +16,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provides a comment-preserving reader and a comment-preserving
+;;; pretty-printer smarter than (ice-9 pretty-print).
+;;;
+;;; Code:
+
 (define-module (guix read-print)
   #:use-module (ice-9 control)
   #:use-module (ice-9 match)
@@ -53,13 +60,6 @@
             comment-margin?
             canonicalize-comment))
 
-;;; Commentary:
-;;;
-;;; This module provides a comment-preserving reader and a comment-preserving
-;;; pretty-printer smarter than (ice-9 pretty-print).
-;;;
-;;; Code:
-
 
 ;;;
 ;;; Comment-preserving reader.
diff --git a/guix/records.scm b/guix/records.scm
index 52d03f73942..fc83d975189 100644
--- a/guix/records.scm
+++ b/guix/records.scm
@@ -17,6 +17,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Utilities for dealing with Scheme records.
+;;;
+;;; Code:
+
 (define-module (guix records)
   #:use-module (srfi srfi-1)
   #:use-module (srfi srfi-9)
@@ -34,12 +40,6 @@
             match-record
             match-record-lambda))
 
-;;; Commentary:
-;;;
-;;; Utilities for dealing with Scheme records.
-;;;
-;;; Code:
-
 (define-syntax record-error
   (syntax-rules ()
     "Report a syntactic error in use of CONSTRUCTOR."
diff --git a/guix/remote-procedures.scm b/guix/remote-procedures.scm
index dca491a76d3..48424f7e8bb 100644
--- a/guix/remote-procedures.scm
+++ b/guix/remote-procedures.scm
@@ -16,6 +16,15 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module defines the remote procedure interface between the build
+;;; daemon and clients (also known as "remote procedure calls" or RPCs).  It
+;;; is used to generate client stubs in (guix store) and can also be used to
+;;; generate server stubs.
+;;;
+;;; Code:
+
 (define-module (guix remote-procedures)
   #:use-module (guix serialization)
   #:export (%protocol-version
@@ -35,15 +44,6 @@
             build-mode
             gc-action))
 
-;;; Comment:
-;;;
-;;; This module defines the remote procedure interface between the build
-;;; daemon and clients (also known as "remote procedure calls" or RPCs).  It
-;;; is used to generate client stubs in (guix store) and can also be used to
-;;; generate server stubs.
-;;;
-;;; Code:
-
 (define %protocol-version
   ;; Version of the currently-implemented protocol.
   #x164)
diff --git a/guix/remote.scm b/guix/remote.scm
index 6a122724936..16a94aef7f8 100644
--- a/guix/remote.scm
+++ b/guix/remote.scm
@@ -16,6 +16,17 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Note: This API is experimental and subject to change!
+;;;
+;;; Evaluate a gexp on a remote machine, over SSH, ensuring that all the
+;;; elements the gexp refers to are deployed beforehand.  This is useful for
+;;; expressions that have side effects; for pure expressions, you would rather
+;;; build a derivation remotely or offload it.
+;;;
+;;; Code:
+
 (define-module (guix remote)
   #:use-module (guix ssh)
   #:use-module (guix gexp)
@@ -36,17 +47,6 @@
   #:use-module (srfi srfi-71)
   #:export (remote-eval))
 
-;;; Commentary:
-;;;
-;;; Note: This API is experimental and subject to change!
-;;;
-;;; Evaluate a gexp on a remote machine, over SSH, ensuring that all the
-;;; elements the gexp refers to are deployed beforehand.  This is useful for
-;;; expressions that have side effects; for pure expressions, you would rather
-;;; build a derivation remotely or offload it.
-;;;
-;;; Code:
-
 (define* (remote-pipe-for-gexp lowered session #:optional become-command)
   "Return a remote pipe for the given SESSION to evaluate LOWERED.  If
 BECOME-COMMAND is given, use that to invoke the remote Guile REPL."
diff --git a/guix/repl.scm b/guix/repl.scm
index 94d85815ef4..0cfcee9ac60 100644
--- a/guix/repl.scm
+++ b/guix/repl.scm
@@ -16,13 +16,6 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
-(define-module (guix repl)
-  #:use-module (srfi srfi-1)
-  #:use-module (srfi srfi-26)
-  #:use-module (ice-9 match)
-  #:export (send-repl-response
-            machine-repl))
-
 ;;; Commentary:
 ;;;
 ;;; This module implements the "machine-readable" REPL provided by
@@ -31,6 +24,13 @@
 ;;;
 ;;; Code:
 
+(define-module (guix repl)
+  #:use-module (srfi srfi-1)
+  #:use-module (srfi srfi-26)
+  #:use-module (ice-9 match)
+  #:export (send-repl-response
+            machine-repl))
+
 (define (self-quoting? x)
   "Return #t if X is self-quoting."
   (letrec-syntax ((one-of (syntax-rules ()
diff --git a/guix/rpm.scm b/guix/rpm.scm
index 34ecab89566..54b444ffdd7 100644
--- a/guix/rpm.scm
+++ b/guix/rpm.scm
@@ -16,6 +16,14 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provides the building blocks required to construct RPM
+;;; archives.  It is intended to be importable on the build side, so shouldn't
+;;; depend on (guix diagnostics) or other host-side-only modules.
+;;;
+;;; Code:
+
 (define-module (guix rpm)
   #:autoload (gcrypt hash) (hash-algorithm file-hash md5)
   #:use-module (guix build utils)
@@ -45,14 +53,6 @@
 
             fhs-directory?))
 
-;;; Commentary:
-;;;
-;;; This module provides the building blocks required to construct RPM
-;;; archives.  It is intended to be importable on the build side, so shouldn't
-;;; depend on (guix diagnostics) or other host-side-only modules.
-;;;
-;;; Code:
-
 (define (gnu-system-triplet->machine-type triplet)
   "Return the machine component of TRIPLET, a GNU system triplet."
   (first (string-split triplet #\-)))
diff --git a/guix/scripts.scm b/guix/scripts.scm
index c4849816ea9..2151acf2a54 100644
--- a/guix/scripts.scm
+++ b/guix/scripts.scm
@@ -21,6 +21,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; General code for Guix scripts.
+;;;
+;;; Code:
+
 (define-module (guix scripts)
   #:use-module (guix utils)
   #:use-module (guix ui)
@@ -52,12 +58,6 @@
             %disk-space-warning
             warn-about-disk-space))
 
-;;; Commentary:
-;;;
-;;; General code for Guix scripts.
-;;;
-;;; Code:
-
 ;; Syntactic keywords.
 (define synopsis 'command-synopsis)
 (define category 'command-category)
diff --git a/guix/scripts/authenticate.scm b/guix/scripts/authenticate.scm
index f90eeeec8de..41540036b31 100644
--- a/guix/scripts/authenticate.scm
+++ b/guix/scripts/authenticate.scm
@@ -16,6 +16,14 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This program is used internally by the daemon to sign exported archive
+;;; (the 'export-paths' RPC), and to authenticate imported archives (the
+;;; 'import-paths' RPC.)
+;;;
+;;; Code:
+
 (define-module (guix scripts authenticate)
   #:use-module (guix scripts)
   #:use-module (guix base16)
@@ -34,14 +42,6 @@
   #:use-module (ice-9 iconv)
   #:export (guix-authenticate))
 
-;;; Commentary:
-;;;
-;;; This program is used internally by the daemon to sign exported archive
-;;; (the 'export-paths' RPC), and to authenticate imported archives (the
-;;; 'import-paths' RPC.)
-;;;
-;;; Code:
-
 (define read-canonical-sexp
   ;; Read a gcrypt sexp from a port and return it.
   (compose string->canonical-sexp read-string))
diff --git a/guix/scripts/challenge.scm b/guix/scripts/challenge.scm
index a1f90b78446..1b98b3d66a4 100644
--- a/guix/scripts/challenge.scm
+++ b/guix/scripts/challenge.scm
@@ -16,6 +16,18 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Challenge substitute servers, checking whether they provide the same
+;;; binaries as those built locally.
+;;;
+;;; Here we completely bypass the daemon to access substitutes.  This is
+;;; because we want to be able to report fine-grain information about
+;;; discrepancies: We need to show the URL of the offending nar, its hash, and
+;;; so on.
+;;;
+;;; Code:
+
 (define-module (guix scripts challenge)
   #:use-module (guix ui)
   #:use-module (guix colors)
@@ -62,18 +74,6 @@
 
             guix-challenge))
 
-;;; Commentary:
-;;;
-;;; Challenge substitute servers, checking whether they provide the same
-;;; binaries as those built locally.
-;;;
-;;; Here we completely bypass the daemon to access substitutes.  This is
-;;; because we want to be able to report fine-grain information about
-;;; discrepancies: We need to show the URL of the offending nar, its hash, and
-;;; so on.
-;;;
-;;; Code:
-
 (define ensure-store-item                         ;XXX: move to (guix ui)?
   (@@ (guix scripts size) ensure-store-item))
 
diff --git a/guix/scripts/deploy.scm b/guix/scripts/deploy.scm
index f1df8bd5e9e..9cad49b857b 100644
--- a/guix/scripts/deploy.scm
+++ b/guix/scripts/deploy.scm
@@ -20,6 +20,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This program provides a command-line interface to (gnu machine), allowing
+;;; users to perform remote deployments through specification files.
+;;;
+;;; Code:
+
 (define-module (guix scripts deploy)
   #:use-module (gnu machine)
   #:use-module (guix discovery)
@@ -41,13 +48,6 @@
   #:use-module (srfi srfi-71)
   #:export (guix-deploy))
 
-;;; Commentary:
-;;;
-;;; This program provides a command-line interface to (gnu machine), allowing
-;;; users to perform remote deployments through specification files.
-;;;
-;;; Code:
-
 
 
 (define (show-help)
diff --git a/guix/scripts/git/authenticate.scm b/guix/scripts/git/authenticate.scm
index 4809e49c7bf..6ff1afe4606 100644
--- a/guix/scripts/git/authenticate.scm
+++ b/guix/scripts/git/authenticate.scm
@@ -17,6 +17,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Authenticate a Git checkout by reading '.guix-authorizations' files and
+;;; following the "authorizations invariant" also used by (guix channels).
+;;;
+;;; Code:
+
 (define-module (guix scripts git authenticate)
   #:use-module (git)
   #:use-module (guix build utils)
@@ -40,13 +47,6 @@
   #:use-module (ice-9 match)
   #:export (guix-git-authenticate))
 
-;;; Commentary:
-;;;
-;;; Authenticate a Git checkout by reading '.guix-authorizations' files and
-;;; following the "authorizations invariant" also used by (guix channels).
-;;;
-;;; Code:
-
 (define %options
   ;; Specifications of the command-line options.
   (list (option '(#\h "help") #f #f
diff --git a/guix/scripts/home/import.scm b/guix/scripts/home/import.scm
index 15b4bc97982..0d6c73ebd39 100644
--- a/guix/scripts/home/import.scm
+++ b/guix/scripts/home/import.scm
@@ -20,6 +20,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provides utilities for generating home service
+;;; configurations from existing "dotfiles".
+;;;
+;;; Code:
+
 (define-module (guix scripts home import)
   #:use-module (guix profiles)
   #:use-module (guix ui)
@@ -39,13 +46,6 @@
             ;; For tests.
             manifest+configuration-files->code))
 
-;;; Commentary:
-;;;
-;;; This module provides utilities for generating home service
-;;; configurations from existing "dotfiles".
-;;;
-;;; Code:
-
 (define (basename+remove-dots file-name)
   "Remove the dot from the dotfile FILE-NAME; replace the other dots in
 FILE-NAME with \"-\", and return the basename of it."
diff --git a/guix/scripts/offload.scm b/guix/scripts/offload.scm
index 462c3dfc0c0..1b694084b31 100644
--- a/guix/scripts/offload.scm
+++ b/guix/scripts/offload.scm
@@ -19,6 +19,18 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Attempt to offload builds to the machines listed in
+;;; /etc/guix/machines.scm, transferring missing dependencies over SSH, and
+;;; retrieving the build output(s) over SSH upon success.
+;;;
+;;; This command should not be used directly; instead, it is called on-demand
+;;; by the daemon, unless it was started with '--no-offload' or a client
+;;; inhibited build hooks.
+;;;
+;;; Code:
+
 (define-module (guix scripts offload)
   #:autoload   (ssh key) (private-key-from-file
                           public-key-from-file)
@@ -76,18 +88,6 @@
 
             guix-offload))
 
-;;; Commentary:
-;;;
-;;; Attempt to offload builds to the machines listed in
-;;; /etc/guix/machines.scm, transferring missing dependencies over SSH, and
-;;; retrieving the build output(s) over SSH upon success.
-;;;
-;;; This command should not be used directly; instead, it is called on-demand
-;;; by the daemon, unless it was started with '--no-offload' or a client
-;;; inhibited build hooks.
-;;;
-;;; Code:
-
 (define-record-type* <build-machine>
   build-machine make-build-machine
   build-machine?
diff --git a/guix/scripts/pack.scm b/guix/scripts/pack.scm
index dbaff4a89c0..cf89cde31bc 100644
--- a/guix/scripts/pack.scm
+++ b/guix/scripts/pack.scm
@@ -28,6 +28,14 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module implements the 'guix pack' command and the various supported
+;;; formats.  Where feasible, the builders of the packs should be implemented
+;;; as single derivations to minimize storage requirements.
+;;;
+;;; Code:
+
 (define-module (guix scripts pack)
   #:use-module (guix scripts)
   #:autoload   (guix import json) (json->scheme-file)
@@ -85,14 +93,6 @@
 
             wrapped-manifest))
 
-;;; Commentary:
-
-;;; This module implements the 'guix pack' command and the various supported
-;;; formats.  Where feasible, the builders of the packs should be implemented
-;;; as single derivations to minimize storage requirements.
-
-;;; Code:
-
 ;; This one is only for use in this module, so don't put it in %compressors.
 (define (bootstrap-xz)
   (compressor "bootstrap-xz" ".xz"
diff --git a/guix/scripts/repl.scm b/guix/scripts/repl.scm
index cb71e59b05f..8bfc5ed1bc1 100644
--- a/guix/scripts/repl.scm
+++ b/guix/scripts/repl.scm
@@ -18,6 +18,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This command provides a Guile script runner and REPL in an environment
+;;; that contains all the modules comprising Guix.
+;;;
+;;; Code:
+
 (define-module (guix scripts repl)
   #:use-module (guix ui)
   #:use-module (guix scripts)
@@ -31,11 +38,6 @@
                   (make-tcp-server-socket make-unix-domain-server-socket)
   #:export (guix-repl))
 
-;;; Commentary:
-;;;
-;;; This command provides a Guile script runner and REPL in an environment
-;;; that contains all the modules comprising Guix.
-
 (define %default-options
   `((type . guile)))
 
diff --git a/guix/scripts/substitute.scm b/guix/scripts/substitute.scm
index 96d8c13ac2c..019269102b2 100755
--- a/guix/scripts/substitute.scm
+++ b/guix/scripts/substitute.scm
@@ -19,6 +19,17 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This is the "binary substituter".  It is invoked by the daemon do check
+;;; for the existence of available "substitutes" (pre-built binaries), and to
+;;; actually use them as a substitute to building things locally.
+;;;
+;;; If possible, substitute a binary for the requested store path, using a Nix
+;;; "binary cache".  This program implements the Nix "substituter" protocol.
+;;;
+;;; Code:
+
 (define-module (guix scripts substitute)
   #:use-module (guix ui)
   #:use-module (guix scripts)
@@ -64,17 +75,6 @@
             substitute-urls
             guix-substitute))
 
-;;; Comment:
-;;;
-;;; This is the "binary substituter".  It is invoked by the daemon do check
-;;; for the existence of available "substitutes" (pre-built binaries), and to
-;;; actually use them as a substitute to building things locally.
-;;;
-;;; If possible, substitute a binary for the requested store path, using a Nix
-;;; "binary cache".  This program implements the Nix "substituter" protocol.
-;;;
-;;; Code:
-
 (define %narinfo-expired-cache-entry-removal-delay
   ;; How often we want to remove files corresponding to expired cache entries.
   (* 5 24 3600))
diff --git a/guix/scripts/system/installer.scm b/guix/scripts/system/installer.scm
index 7a26896a872..5ea38043320 100644
--- a/guix/scripts/system/installer.scm
+++ b/guix/scripts/system/installer.scm
@@ -16,6 +16,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Implement the 'guix system installer' command, which runs the installer,
+;;; directly as a Guix command, also in dry-run mode.
+;;;
+;;; Code:
+
 (define-module (guix scripts system installer)
   #:use-module (srfi srfi-1)
   #:use-module (srfi srfi-37)
@@ -25,13 +32,6 @@
   #:use-module (guix utils)
   #:export (guix-system-installer))
 
-;;; Commentary:
-;;;
-;;; Implement the 'guix system installer' command, which runs the installer,
-;;; directly as a Guix command, also in dry-run mode.
-;;;
-;;; Code:
-
 (define %options
   (list (option '(#\n "dry-run") #f #f
                 (lambda (opt name arg result)
diff --git a/guix/scripts/system/reconfigure.scm b/guix/scripts/system/reconfigure.scm
index 402e6d30fc1..74430991862 100644
--- a/guix/scripts/system/reconfigure.scm
+++ b/guix/scripts/system/reconfigure.scm
@@ -24,6 +24,16 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module implements the "effectful" parts of system
+;;; reconfiguration. Although building a system derivation is a pure
+;;; operation, a number of impure operations must be carried out for the
+;;; system configuration to be realized -- chiefly, creation of generation
+;;; symlinks and invocation of activation scripts.
+;;;
+;;; Code:
+
 (define-module (guix scripts system reconfigure)
   #:autoload   (gnu packages gnupg) (guile-gcrypt)
   #:use-module (gnu bootloader)
@@ -64,16 +74,6 @@
             ensure-forward-reconfigure
             warn-about-backward-reconfigure))
 
-;;; Commentary:
-;;;
-;;; This module implements the "effectful" parts of system
-;;; reconfiguration. Although building a system derivation is a pure
-;;; operation, a number of impure operations must be carried out for the
-;;; system configuration to be realized -- chiefly, creation of generation
-;;; symlinks and invocation of activation scripts.
-;;;
-;;; Code:
-
 
 ;;;
 ;;; Profile creation.
diff --git a/guix/scripts/system/search.scm b/guix/scripts/system/search.scm
index d978884518e..626fbdb8430 100644
--- a/guix/scripts/system/search.scm
+++ b/guix/scripts/system/search.scm
@@ -17,6 +17,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Implement the 'guix system search' command, which searches among the
+;;; available service types.
+;;;
+;;; Code:
+
 (define-module (guix scripts system search)
   #:use-module (guix ui)
   #:use-module (guix utils)
@@ -35,13 +42,6 @@
             find-service-types
             guix-system-search))
 
-;;; Commentary:
-;;;
-;;; Implement the 'guix system search' command, which searches among the
-;;; available service types.
-;;;
-;;; Code:
-
 (define service-type-name*
   (compose symbol->string service-type-name))
 
diff --git a/guix/search-paths.scm b/guix/search-paths.scm
index 90939d6aca6..1e72a2708b5 100644
--- a/guix/search-paths.scm
+++ b/guix/search-paths.scm
@@ -18,6 +18,15 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module defines "search path specifications", which allow packages to
+;;; declare environment variables that they use to define search paths.  For
+;;; instance, GCC has the 'CPATH' variable, Guile has the 'GUILE_LOAD_PATH'
+;;; variable, etc.
+;;;
+;;; Code:
+
 (define-module (guix search-paths)
   #:use-module (guix records)
   #:use-module (guix build utils)
@@ -59,15 +68,6 @@
             search-path-definition
             set-search-paths))
 
-;;; Commentary:
-;;;
-;;; This module defines "search path specifications", which allow packages to
-;;; declare environment variables that they use to define search paths.  For
-;;; instance, GCC has the 'CPATH' variable, Guile has the 'GUILE_LOAD_PATH'
-;;; variable, etc.
-;;;
-;;; Code:
-
 ;; The specification of a search path.
 (define-record-type* <search-path-specification>
   search-path-specification make-search-path-specification
diff --git a/guix/serialization.scm b/guix/serialization.scm
index 54ff5da03d9..480dc04182e 100644
--- a/guix/serialization.scm
+++ b/guix/serialization.scm
@@ -16,6 +16,14 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+
+;;; Commentary:
+;;;
+;;; Serialization procedures used by the RPCs and the Nar format.  This module
+;;; is for internal consumption.
+;;;
+;;; Code:
+
 (define-module (guix serialization)
   #:autoload   (guix base16) (base16-string->bytevector
                               bytevector->base16-string)
@@ -78,13 +86,6 @@
             restore-file
             dump-file))
 
-;;; Comment:
-;;;
-;;; Serialization procedures used by the RPCs and the Nar format.  This module
-;;; is for internal consumption.
-;;;
-;;; Code:
-
 ;; Similar to serialize.cc in Nix.
 
 (define-condition-type &nar-error &error      ; XXX: inherit from &store-error ?
diff --git a/guix/sets.scm b/guix/sets.scm
index 017b79ca31d..de94f327230 100644
--- a/guix/sets.scm
+++ b/guix/sets.scm
@@ -16,6 +16,17 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; A simple (simplistic?) implementation of unordered persistent sets based
+;;; on vhashes that seems to be good enough so far.
+;;;
+;;; Another option would be to use "bounded balance trees" (Adams 1992) as
+;;; implemented by Ian Price in 'pfds', which has faster union etc. but needs
+;;; an order on the objects of the set.
+;;;
+;;; Code:
+
 (define-module (guix sets)
   #:use-module (srfi srfi-1)
   #:use-module (srfi srfi-9)
@@ -32,17 +43,6 @@
             list->set
             list->setq))
 
-;;; Commentary:
-;;;
-;;; A simple (simplistic?) implementation of unordered persistent sets based
-;;; on vhashes that seems to be good enough so far.
-;;;
-;;; Another option would be to use "bounded balance trees" (Adams 1992) as
-;;; implemented by Ian Price in 'pfds', which has faster union etc. but needs
-;;; an order on the objects of the set.
-;;;
-;;; Code:
-
 (define-record-type <set>
   (%make-set vhash insert ref)
   set?
diff --git a/guix/ssh.scm b/guix/ssh.scm
index 4a28432dcee..e91d1c19c55 100644
--- a/guix/ssh.scm
+++ b/guix/ssh.scm
@@ -16,6 +16,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provides tools to support communication with remote stores
+;;; over SSH, using Guile-SSH.
+;;;
+;;; Code:
+
 (define-module (guix ssh)
   #:use-module (guix store)
   #:use-module (guix inferior)
@@ -56,13 +63,6 @@
 
             report-guile-error))
 
-;;; Commentary:
-;;;
-;;; This module provides tools to support communication with remote stores
-;;; over SSH, using Guile-SSH.
-;;;
-;;; Code:
-
 (define %compression
   "zlib@openssh.com,zlib,none")
 
diff --git a/guix/status.scm b/guix/status.scm
index d3e926912c5..1404e40c56f 100644
--- a/guix/status.scm
+++ b/guix/status.scm
@@ -19,6 +19,16 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provides facilities to track the status of ongoing builds and
+;;; downloads in a given session, as well as tools to report about the current
+;;; status to user interfaces.  It does so by analyzing the output of
+;;; 'current-build-output-port'.  The build status is maintained in a
+;;; <build-status> record.
+;;;
+;;; Code:
+
 (define-module (guix status)
   #:use-module (guix records)
   #:use-module (guix i18n)
@@ -77,16 +87,6 @@
             with-status-report
             with-status-verbosity))
 
-;;; Commentary:
-;;;
-;;; This module provides facilities to track the status of ongoing builds and
-;;; downloads in a given session, as well as tools to report about the current
-;;; status to user interfaces.  It does so by analyzing the output of
-;;; 'current-build-output-port'.  The build status is maintained in a
-;;; <build-status> record.
-;;;
-;;; Code:
-
 
 ;;;
 ;;; Build status tracking.
diff --git a/guix/store/roots.scm b/guix/store/roots.scm
index 6b949b5a86e..1fc366fc843 100644
--- a/guix/store/roots.scm
+++ b/guix/store/roots.scm
@@ -16,6 +16,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provides tools to list and access garbage collector roots ("GC
+;;; roots").
+;;;
+;;; Code:
+
 (define-module (guix store roots)
   #:use-module (guix config)
   #:use-module ((guix store) #:select (store-path? %gc-roots-directory))
@@ -34,13 +41,6 @@
             user-owned?
             busy-store-items))
 
-;;; Commentary:
-;;;
-;;; This module provides tools to list and access garbage collector roots ("GC
-;;; roots").
-;;;
-;;; Code:
-
 (define %profile-directory
   ;; Directory where user profiles are stored.
   ;; XXX: This is redundant with the definition in (guix profiles) and not
diff --git a/guix/store/ssh.scm b/guix/store/ssh.scm
index 7e6371acbca..7a09a3b0fe4 100644
--- a/guix/store/ssh.scm
+++ b/guix/store/ssh.scm
@@ -16,18 +16,18 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
-(define-module (guix store ssh)
-  #:use-module (guix ssh)
-  #:use-module (web uri)
-  #:export (connect-to-daemon))
-
 ;;; Commentary:
 ;;;
 ;;; This modules provides the entry point for 'open-connection' in (guix
 ;;; store).  Passing an 'ssh://' URI to 'open-connection' triggers the use of
 ;;; the code in this module.
 ;;;
-;;; End:
+;;; Code:
+
+(define-module (guix store ssh)
+  #:use-module (guix ssh)
+  #:use-module (web uri)
+  #:export (connect-to-daemon))
 
 (define (connect-to-daemon uri)
   "Connect to the SSH daemon at URI, a URI object with the 'ssh' scheme."
diff --git a/guix/svn-download.scm b/guix/svn-download.scm
index 81a98b11214..893c140ca0a 100644
--- a/guix/svn-download.scm
+++ b/guix/svn-download.scm
@@ -18,6 +18,14 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; An <origin> method that fetches a specific revision from a Subversion
+;;; repository.  The repository URL and REVISION are specified with a
+;;; <svn-reference> object.  REVISION should be specified as a number.
+;;;
+;;; Code:
+
 (define-module (guix svn-download)
   #:use-module (guix records)
   #:use-module (guix gexp)
@@ -52,14 +60,6 @@
             svn-multi-fetch
             download-multi-svn-to-store))
 
-;;; Commentary:
-;;;
-;;; An <origin> method that fetches a specific revision from a Subversion
-;;; repository.  The repository URL and REVISION are specified with a
-;;; <svn-reference> object.  REVISION should be specified as a number.
-;;;
-;;; Code:
-
 (define-record-type* <svn-reference>
   svn-reference make-svn-reference
   svn-reference?
diff --git a/guix/swh.scm b/guix/swh.scm
index 0999314707d..98e7dbb230f 100644
--- a/guix/swh.scm
+++ b/guix/swh.scm
@@ -19,6 +19,18 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provides bindings to the HTTP interface of Software Heritage.
+;;; It allows you to browse the archive, look up revisions (such as SHA1
+;;; commit IDs), "origins" (code hosting URLs), content (files), etc.  See
+;;; <https://archive.softwareheritage.org/api/> for more information.
+;;;
+;;; The high-level 'swh-download' procedure allows you to download a Git
+;;; revision from Software Heritage, provided it is available.
+;;;
+;;; Code:
+
 (define-module (guix swh)
   #:use-module (guix base16)
   #:use-module (guix build utils)
@@ -128,18 +140,6 @@
             swh-download-directory-by-nar-hash
             swh-download))
 
-;;; Commentary:
-;;;
-;;; This module provides bindings to the HTTP interface of Software Heritage.
-;;; It allows you to browse the archive, look up revisions (such as SHA1
-;;; commit IDs), "origins" (code hosting URLs), content (files), etc.  See
-;;; <https://archive.softwareheritage.org/api/> for more information.
-;;;
-;;; The high-level 'swh-download' procedure allows you to download a Git
-;;; revision from Software Heritage, provided it is available.
-;;;
-;;; Code:
-
 (define %swh-base-url
   ;; Presumably we won't need to change it.
   (make-parameter "https://archive.softwareheritage.org"))
diff --git a/guix/tests.scm b/guix/tests.scm
index 00787ced20c..4be360a7798 100644
--- a/guix/tests.scm
+++ b/guix/tests.scm
@@ -16,6 +16,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provide shared infrastructure for the test suite.  For
+;;; internal use only.
+;;;
+;;; Code:
+
 (define-module (guix tests)
   #:use-module ((guix config) #:select (%storedir %localstatedir))
   #:use-module (guix store)
@@ -66,13 +73,6 @@
 
             test-file))
 
-;;; Commentary:
-;;;
-;;; This module provide shared infrastructure for the test suite.  For
-;;; internal use only.
-;;;
-;;; Code:
-
 (define %tests-build-timeout
   ;; Timeout limit for guix unit tests (default: 5 minutes)
   (let ((default (if (string=? "riscv64-linux" (%current-system))
diff --git a/guix/tests/http.scm b/guix/tests/http.scm
index 17485df9efd..ac026ba9d56 100644
--- a/guix/tests/http.scm
+++ b/guix/tests/http.scm
@@ -17,6 +17,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Code to spawn a Web server for testing purposes.
+;;;
+;;; Code:
+
 (define-module (guix tests http)
   #:use-module (ice-9 threads)
   #:use-module (web server)
@@ -32,12 +38,6 @@
             %http-server-port
             %local-url))
 
-;;; Commentary:
-;;;
-;;; Code to spawn a Web server for testing purposes.
-;;;
-;;; Code:
-
 (define %http-server-port
   ;; TCP port to use for the stub HTTP server.
   ;; If 0, the OS will automatically choose
diff --git a/guix/transformations.scm b/guix/transformations.scm
index 236527330f6..d0e4e88822a 100644
--- a/guix/transformations.scm
+++ b/guix/transformations.scm
@@ -20,6 +20,14 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module implements "package transformation options"---tools for
+;;; package graph rewriting.  It contains the graph rewriting logic, but also
+;;; the tip of its user interface: command-line option handling.
+;;;
+;;; Code:
+
 (define-module (guix transformations)
   #:use-module ((guix config) #:select (%system))
   #:use-module (guix i18n)
@@ -75,14 +83,6 @@
             cacheable-transformation-option-key?
             %transformation-options))
 
-;;; Commentary:
-;;;
-;;; This module implements "package transformation options"---tools for
-;;; package graph rewriting.  It contains the graph rewriting logic, but also
-;;; the tip of its user interface: command-line option handling.
-;;;
-;;; Code:
-
 (module-autoload! (current-module) '(gnu packages)
                   '(specification->package))
 
diff --git a/guix/ui.scm b/guix/ui.scm
index dafc04b20f7..9235c4f4016 100644
--- a/guix/ui.scm
+++ b/guix/ui.scm
@@ -36,6 +36,16 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; User interface facilities for command-line tools.
+;;;
+;;; Note: This module is meant to be imported by user interfaces only and not
+;;; be "regular" modules.  It depends on lots of modules that may be
+;;; relatively heavyweight dependencies for non-UI modules.
+;;;
+;;; Code:
+
 (define-module (guix ui)                       ;import in user interfaces only
   #:use-module (guix i18n)
   #:use-module (guix colors)
@@ -152,16 +162,6 @@
             run-guix
             guix-main))
 
-;;; Commentary:
-;;;
-;;; User interface facilities for command-line tools.
-;;;
-;;; Note: This module is meant to be imported by user interfaces only and not
-;;; be "regular" modules.  It depends on lots of modules that may be
-;;; relatively heavyweight dependencies for non-UI modules.
-;;;
-;;; Code:
-
 (define (print-unbound-variable-error port key args default-printer)
   ;; Print unbound variable errors more nicely, and in the right language.
   (match args
diff --git a/guix/upstream.scm b/guix/upstream.scm
index 972f674d350..bacba8a8b19 100644
--- a/guix/upstream.scm
+++ b/guix/upstream.scm
@@ -21,6 +21,13 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; This module provides tools to represent and manipulate a upstream source
+;;; code, and to auto-update package recipes.
+;;;
+;;; Code:
+
 (define-module (guix upstream)
   #:use-module (guix records)
   #:use-module (guix utils)
@@ -96,13 +103,6 @@
             package-update
             update-package-source))
 
-;;; Commentary:
-;;;
-;;; This module provides tools to represent and manipulate a upstream source
-;;; code, and to auto-update package recipes.
-;;;
-;;; Code:
-
 ;; Representation of upstream's source.  There can be several URLs--e.g.,
 ;; tar.gz, tar.gz, etc.  There can be correspond signature URLs, one per
 ;; source URL.
diff --git a/guix/workers.scm b/guix/workers.scm
index 3cd683c96d7..8e315a35222 100644
--- a/guix/workers.scm
+++ b/guix/workers.scm
@@ -16,20 +16,6 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
-(define-module (guix workers)
-  #:use-module (ice-9 threads)
-  #:use-module (ice-9 match)
-  #:use-module (ice-9 q)
-  #:use-module (srfi srfi-1)
-  #:use-module (srfi srfi-9)
-  #:use-module (srfi srfi-26)
-  #:use-module ((guix build syscalls) #:select (set-thread-name))
-  #:export (pool?
-            make-pool
-            pool-enqueue!
-            pool-idle?
-            eventually))
-
 ;;; Commentary:
 ;;;
 ;;; This module implements "worker pools".  Worker pools are the low-level
@@ -44,6 +30,20 @@
 ;;;
 ;;; Code:
 
+(define-module (guix workers)
+  #:use-module (ice-9 threads)
+  #:use-module (ice-9 match)
+  #:use-module (ice-9 q)
+  #:use-module (srfi srfi-1)
+  #:use-module (srfi srfi-9)
+  #:use-module (srfi srfi-26)
+  #:use-module ((guix build syscalls) #:select (set-thread-name))
+  #:export (pool?
+            make-pool
+            pool-enqueue!
+            pool-idle?
+            eventually))
+
 (define-record-type <pool>
   (%make-pool queue mutex condvar workers busy)
   pool?
diff --git a/tests/services/vpn.scm b/tests/services/vpn.scm
index 484eefec80d..b7a347df200 100644
--- a/tests/services/vpn.scm
+++ b/tests/services/vpn.scm
@@ -16,6 +16,12 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;;
+;;; Unit tests for the (gnu services vpn) module.
+;;;
+;;; Code:
+
 (define-module (tests services vpn)
   #:use-module (gnu packages vpn)
   #:use-module (gnu services vpn)
@@ -24,12 +30,6 @@
   #:use-module (srfi srfi-1)
   #:use-module (srfi srfi-64))
 
-;;; Commentary:
-;;;
-;;; Unit tests for the (gnu services vpn) module.
-;;;
-;;; Code:
-
 ;;; Access some internals for whitebox testing.
 (define ipv4-address? (@@ (gnu services vpn) ipv4-address?))
 (define ipv6-address? (@@ (gnu services vpn) ipv6-address?))