* doc/emacs/rmail.texi (Rmail Inbox): Mention rmail-mbox-format.

* etc/NEWS: Related markup.

doc/emacs/ChangeLog

@@ -1,3 +1,7 @@
+2014-02-23  Glenn Morris  <rgm@gnu.org>
+
+	* rmail.texi (Rmail Inbox): Mention rmail-mbox-format.
+
 2014-02-20  Glenn Morris  <rgm@gnu.org>
 
 	* search.texi (Special Isearch): Mention invisible text.

doc/emacs/rmail.texi

@@ -356,7 +356,7 @@ Files}.
 @item
 The inbox file format varies between operating systems and according to
 the other mail software in use.  Only one part of Rmail needs to know
-about the alternatives, and it need only understand how to convert all
+about the alternatives, and it need only understand how to convert allx
 of them to Rmail's own format.
 
 @item
@@ -369,12 +369,20 @@ the rest of Rmail, since only Rmail operates on the Rmail file.
 @end enumerate
 
 @c FIXME remove this in Emacs 25; won't be relevant any more.
+@cindex Babyl files
+@cindex mbox files
   Rmail was originally written to use the Babyl format as its internal
 format.  Since then, we have recognized that the usual inbox format
 (@samp{mbox}) on Unix and GNU systems is adequate for the job, and so
 since Emacs 23 Rmail uses that as its internal format.  The Rmail file
 is still separate from the inbox file, even though their format is the
 same.
+@c But this bit should stay in some form.
+@vindex rmail-mbox-format
+(In fact, there are a few slightly different mbox formats.
+The differences are not very important, but you can set the variable
+@code{rmail-mbox-format} to tell Rmail which form your system uses.
+See that variable's documentation for more details.)
 
 @vindex rmail-preserve-inbox
   When getting new mail, Rmail first copies the new mail from the

etc/NEWS

@@ -784,6 +784,7 @@ names specified by `remember-directory-file-name-format'.
 
 ** Rmail
 
++++
 *** Customize `rmail-mbox-format' to influence some minor aspects of
 how Rmail displays non-MIME messages.