diff --git a/admin/admin.el b/admin/admin.el
index 90bef11baf9..542556a65e0 100644
--- a/admin/admin.el
+++ b/admin/admin.el
@@ -98,6 +98,10 @@ Optional argument DATE is the release date, default today."
 (defvar admin-git-command (executable-find "git")
   "The `git' program to use.")
 
+(defvar admin-android-version-code-regexp
+  "\\bAuto-incrementing version code\\(?:.\\|\n\\)*\\([[:digit:]]\\{9\\}\\)$"
+  "Regexp with which to detect the version code in AndroidManifest.xml.")
+
 (defun set-version (root version)
   "Set Emacs version to VERSION in relevant files under ROOT.
 Root must be the root of an Emacs source tree."
@@ -122,6 +126,11 @@ Root must be the root of an Emacs source tree."
 		       (rx (and "AC_INIT" (1+ (not (in ?,)))
                                 ?, (0+ space) ?\[
                                 (submatch (1+ (in "0-9."))))))
+  (set-version-in-file root "java/AndroidManifest.xml.in"
+                       (apply #'format "%02d%02d%02d000"
+                              (mapcar #'string-to-number
+                                      (split-string version "\\.")))
+                       admin-android-version-code-regexp)
   (set-version-in-file root "nt/README.W32" version
 		       (rx (and "version" (1+ space)
 				(submatch (1+ (in "0-9."))))))
diff --git a/java/AndroidManifest.xml.in b/java/AndroidManifest.xml.in
index c066d91011a..66b26e65088 100644
--- a/java/AndroidManifest.xml.in
+++ b/java/AndroidManifest.xml.in
@@ -338,3 +338,18 @@ along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>. -->
 	     android:label="GNU Emacs service"/>
   </application>
 </manifest>
+
+<!-- Auto-incrementing version code.
+
+This comment contains an Android version code
+(https://developer.android.com/studio/publish/versioning#versioningsettings)
+corresponding to the current Emacs version.  The version code in
+AndroidManifest.xml.in is hard-coded to a fixed value to facilitate
+package downgrades.  Some automated systems employed by Android package
+repositories require an incrementing numeric version code to detect
+upgrades, which is provided here and is altered by admin/admin.el.
+Refer to e.g. https://forum.f-droid.org/t/emacs-packaging/30424/25.
+
+Version-code: 300050000
+
+-->
diff --git a/java/incrementing-version-code b/java/incrementing-version-code
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/lisp/emacs-lisp/shortdoc.el b/lisp/emacs-lisp/shortdoc.el
index 77a4ec4f21c..15898ac9687 100644
--- a/lisp/emacs-lisp/shortdoc.el
+++ b/lisp/emacs-lisp/shortdoc.el
@@ -1607,10 +1607,12 @@ A FUNC form can have any number of `:no-eval' (or `:no-value'),
 ;;;###autoload
 (defun shortdoc-display-group (group &optional function same-window)
   "Pop to a buffer with short documentation summary for functions in GROUP.
+Interactively, prompt for GROUP.
 If FUNCTION is non-nil, place point on the entry for FUNCTION (if any).
 If SAME-WINDOW, don't pop to a new window."
-  (interactive (list (completing-read "Show summary for functions in: "
-                                      (mapcar #'car shortdoc--groups))))
+  (interactive (list (completing-read
+                      "Group of functions for which to show summary: "
+                      (mapcar #'car shortdoc--groups))))
   (when (stringp group)
     (setq group (intern group)))
   (unless (assq group shortdoc--groups)
diff --git a/lisp/register.el b/lisp/register.el
index 0e9d5676943..a338eb586d2 100644
--- a/lisp/register.el
+++ b/lisp/register.el
@@ -147,7 +147,10 @@ all; the preview buffer is still accessible with `help-char' (\\`C-h').
 
 When set to `traditional' (the default), provide a more basic preview
 according to `register-preview-delay'; this preserves the traditional
-behavior of Emacs 29 and before."
+behavior of Emacs 29 and before.
+
+Setting this variable with `setq' has no effect; use either `setopt'
+or `customize-option' to change its value."
   :type '(choice
           (const :tag "Use preview" t)
           (const :tag "Use preview and exit by pressing register name" insist)