* doc/misc/efaq-w32.texi (UTF-8 encoding): New section (bug#79296).

doc/misc/efaq-w32.texi

@@ -913,6 +913,7 @@ The doc string contains a list of the system sounds you can use.
 * Multilingual fonts::
 * Font menu::
 * Line ends::
+* UTF-8 encoding::
 @end menu
 
 @node Font names
@@ -1191,6 +1192,69 @@ recent versions of Emacs, this is seldom useful for existing files,
 but can still be used to influence the choice of line ends for newly
 created files.
 
+@node UTF-8 encoding
+@section Can I use UTF-8 as default encoding on MS-Windows?
+@cindex UTF-8 as default encoding on Windows
+@cindex codepage 65001 support in Emacs
+
+Recent versions of MS-Windows (Windows 10 since build 1803, and Windows
+11 or later versions) allow to use UTF-8 (a.k.a.@: ``codepage 65001'')
+as the default system codepage.  As of this writing, this is still an
+experimental feature, even in Windows 11, and is disabled by default.
+On Windows 11 you can enable it as follows:
+
+@enumerate
+@item
+Open Settings.
+
+@item
+Select ``Time & Language'', then ``Language & region''.
+
+@item
+Click on ``Administrative language settings''.
+
+@item
+On the dialog that pops up click ``Change system locale...''
+
+@item
+In the ``Region Settings'' dialog that pops up, check the check-box
+labeled ``Beta: Use Unicode UTF-8 for worldwide language support'', then
+confirm by clicking ``OK'' to both dialogs.
+@end enumerate
+
+@cindex UCRT runtime library
+@cindex MSVCRT runtime library
+Emacs supports this feature starting from version 30.2, but only when
+running on the versions of Windows that provide this feature, and only
+if the Emacs executable was linked against the @samp{UCRT} library as
+the Windows C runtime, not against the older @samp{MSVCRT}.  This is
+because the C functions that deal with non-ASCII characters, as
+implemented by @samp{MSVCRT}, don't support UTF-8 as the multibyte
+encoding of non-ASCII characters.  (Which runtime to link against is
+determined by the person who built your Emacs binary.  Note that using
+Emacs linked against @samp{UCRT} needs all of the libraries loaded by
+Emacs dynamically, such as GnuTLS, image libraries like @samp{rsvg},
+Tree-sitter, and all the others, to be also linked against @samp{UCRT},
+otherwise subtle problems could happen when dealing with non-ASCII
+characters and strings.)
+
+If you have an Emacs linked against @samp{UCRT}, and you turned on the
+UTF-8 support in Windows as described above, you can customize Emacs to
+use UTF-8 as your default encoding, e.g., by adding
+
+@lisp
+ (prefer-coding-system 'utf-8)
+@end lisp
+
+@noindent
+to your init file, or by using the @samp{UTF-8} language environment
+(@pxref{Language Environments,,, emacs, The GNU Emacs Manual}) in your
+Emacs sessions.
+
+Please be aware that, since this feature of Windows is still in beta,
+there could be some subtle issues with it.  So we do not yet recommend
+to turn this on, unless you feel adventurous.
+
 @c ------------------------------------------------------------
 @node Printing
 @chapter Printing