diff --git a/doc/emacs/files.texi b/doc/emacs/files.texi
index c7d3b40f9d15..6c68075ae4a6 100644
--- a/doc/emacs/files.texi
+++ b/doc/emacs/files.texi
@@ -932,10 +932,11 @@ way that, if the file was edited only slightly, you will be at
 approximately the same part of the text as before.  But if you have
 made major changes, point may end up in a totally different location.
 
-  Reverting marks the buffer as not modified.  It also clears the
-buffer's undo history (@pxref{Undo}).  Thus, the reversion cannot be
-undone---if you change your mind yet again, you can't use the undo
-commands to bring the reverted changes back.
+  Reverting marks the buffer as not modified.  However, it adds the
+reverted changes as a single modification to the buffer's undo history
+(@pxref{Undo}).  Thus, after reverting, you can type @kbd{C-/} or its
+aliases to bring the reverted changes back, if you happen to change
+your mind.
 
   Some kinds of buffers that are not associated with files, such as
 Dired buffers, can also be reverted.  For them, reverting means
diff --git a/doc/misc/dired-x.texi b/doc/misc/dired-x.texi
index 36a9cb0291ad..f65542f02ea9 100644
--- a/doc/misc/dired-x.texi
+++ b/doc/misc/dired-x.texi
@@ -321,8 +321,8 @@ Default: @code{nil}
 
 @cindex How to make omitting the default in Dired
 If non-@code{nil}, ``uninteresting'' files are not listed.
-Uninteresting files are those whose files whose names match regexp
-@code{dired-omit-files}, plus those ending with extensions in
+Uninteresting files are files whose names match regexp
+@code{dired-omit-files}, plus files whose names end with extension in
 @code{dired-omit-extensions}.  @kbd{C-x M-o} (@code{dired-omit-mode})
 toggles its value, which is buffer-local.  Put
 
diff --git a/doc/misc/efaq.texi b/doc/misc/efaq.texi
index 26d9c82b2195..0d4e4ba8bddf 100644
--- a/doc/misc/efaq.texi
+++ b/doc/misc/efaq.texi
@@ -3536,7 +3536,7 @@ see @ref{Packages that do not come with Emacs}.
 
 The easiest way to add more features to your Emacs is to use the
 command @kbd{M-x list-packages}.  This contacts the
-@uref{https:///elpa.gnu.org, GNU ELPA} (``Emacs Lisp Package Archive'')
+@uref{https://elpa.gnu.org, GNU ELPA} (``Emacs Lisp Package Archive'')
 server and fetches the list of additional packages that it offers.
 These are GNU packages that are available for use with Emacs, but are
 distributed separately from Emacs itself, for reasons of space, etc.
@@ -3545,8 +3545,8 @@ available, and then Emacs can automatically download and install the
 packages that you select.  @xref{Packages,,, emacs, The GNU Emacs Manual}.
 
 There are other, non-GNU, Emacs Lisp package servers, including:
-@uref{http://melpa.org/, MELPA}; and
-@uref{https://marmalade-repo.org/, Marmalade}.  To use additional
+@uref{https://melpa.org, MELPA}; and
+@uref{https://marmalade-repo.org, Marmalade}.  To use additional
 package servers, customize the @code{package-archives} variable.  Be
 aware that installing a package can run arbitrary code, so only add
 sources that you trust.
@@ -3557,8 +3557,8 @@ GNU Emacs sources mailing list}, which is gatewayed to the
 connection between the two can be unreliable) is an official place
 where people can post or announce their extensions to Emacs.
 
-The @uref{http://emacswiki.org, Emacs Wiki} contains pointers to some
-additional extensions.  @uref{http://wikemacs.org, WikEmacs} is an
+The @uref{https://emacswiki.org, Emacs Wiki} contains pointers to some
+additional extensions.  @uref{https://wikemacs.org, WikEmacs} is an
 alternative wiki for Emacs.
 
 @uref{http://www.damtp.cam.ac.uk/user/sje30/emacs/ell.html, The Emacs
diff --git a/etc/NEWS b/etc/NEWS
index 7a98b492f136..ce849e49909f 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -21,6 +21,12 @@ Temporary note:
 --- means no change in the manuals is needed.
 When you add a new item, use the appropriate mark if you are sure it applies,
 
++++
+** Installing Emacs now installs the emacs-module.h file.
+The emacs-module.h file is now installed in the system-wide include
+directory as part of the Emacs installation.  This allows to build
+Emacs modules outside of the Emacs source tree.
+
 
 * Installation Changes in Emacs 27.1
 
diff --git a/lisp/dired-aux.el b/lisp/dired-aux.el
index 90bfa096b082..72c16da63f8c 100644
--- a/lisp/dired-aux.el
+++ b/lisp/dired-aux.el
@@ -1738,7 +1738,7 @@ or with the current marker character if MARKER-CHAR is t."
           (let* ((overwrite (file-exists-p to))
                  (dired-overwrite-confirmed ; for dired-handle-overwrite
                   (and overwrite
-                       (let ((help-form '(format-message "\
+                       (let ((help-form (format-message "\
 Type SPC or `y' to overwrite file `%s',
 DEL or `n' to skip to next,
 ESC or `q' to not overwrite any of the remaining files,
diff --git a/lisp/gnus/gnus-art.el b/lisp/gnus/gnus-art.el
index 1b0dde94551a..f28e6db3c7e5 100644
--- a/lisp/gnus/gnus-art.el
+++ b/lisp/gnus/gnus-art.el
@@ -2243,9 +2243,7 @@ This only works if the article in question is HTML."
 		     start end)))))))
 
 (defun gnus-article-treat-fold-newsgroups ()
-  "Unfold folded message headers.
-Only the headers that fit into the current window width will be
-unfolded."
+  "Fold the Newsgroups and Followup-To message headers."
   (interactive)
   (gnus-with-article-headers
     (while (gnus-article-goto-header "newsgroups\\|followup-to")
diff --git a/lisp/mail/smtpmail.el b/lisp/mail/smtpmail.el
index 9b045b255845..8a1e86b77500 100644
--- a/lisp/mail/smtpmail.el
+++ b/lisp/mail/smtpmail.el
@@ -397,35 +397,35 @@ for `smtpmail-try-auth-method'.")
   (with-temp-buffer
     ;; Get index, get first mail, send it, update index, get second
     ;; mail, send it, etc...
-    (let ((file-msg "")
+    (let (file-data file-elisp
           (qfile (expand-file-name smtpmail-queue-index-file
                                    smtpmail-queue-dir))
 	  result)
       (insert-file-contents qfile)
       (goto-char (point-min))
       (while (not (eobp))
-	(setq file-msg (buffer-substring (point) (line-end-position)))
+	(setq file-data (buffer-substring (point) (line-end-position)))
+	(setq file-elisp (concat file-data ".el"))
         ;; FIXME: Avoid `load' which can execute arbitrary code and is hence
         ;; a source of security holes.  Better read the file and extract the
         ;; data "by hand".
-	;;(load file-msg)
+	;;(load file-elisp)
         (with-temp-buffer
-          (insert-file-contents (concat file-msg ".el"))
+          (insert-file-contents file-elisp)
           (goto-char (point-min))
           (pcase (read (current-buffer))
             (`(setq smtpmail-recipient-address-list ',v)
              (skip-chars-forward " \n\t")
              (unless (eobp) (message "Ignoring trailing text in %S"
-                                     (concat file-msg ".el")))
+                                     file-elisp))
              (setq smtpmail-recipient-address-list v))
-            (sexp (error "Unexpected code in %S: %S"
-                         (concat file-msg ".el") sexp))))
+            (sexp (error "Unexpected code in %S: %S" file-elisp sexp))))
 	;; Insert the message literally: it is already encoded as per
 	;; the MIME headers, and code conversions might guess the
 	;; encoding wrongly.
 	(with-temp-buffer
 	  (let ((coding-system-for-read 'no-conversion))
-	    (insert-file-contents file-msg))
+	    (insert-file-contents file-data))
           (let ((smtpmail-mail-address
                  (or (and mail-specify-envelope-from (mail-envelope-from))
                      user-mail-address)))
@@ -435,8 +435,8 @@ for `smtpmail-try-auth-method'.")
 				    (current-buffer)))
 		  (error "Sending failed: %s" result))
               (error "Sending failed; no recipients"))))
-	(delete-file file-msg)
-	(delete-file (concat file-msg ".el"))
+	(delete-file file-data)
+	(delete-file file-elisp)
 	(delete-region (point-at-bol) (point-at-bol 2)))
       (write-region (point-min) (point-max) qfile))))