2 files changed, 14 insertions, 0 deletions

diff --git a/doc/lispref/ChangeLog b/doc/lispref/ChangeLog
index 07d153ed80e..af09f4371f9 100644
--- a/doc/lispref/ChangeLog
+++ b/doc/lispref/ChangeLog
@@ -1,5 +1,8 @@
 2013-12-18  Chong Yidong  <cyd@gnu.org>
 
+        * customize.texi (Custom Themes): Document custom-known-themes
+        (Bug#15717).
+
         * modes.texi (Defining Minor Modes): Fix typo (Bug#14874).
         (Keymaps and Minor Modes): Fix binding convention (Bug#11522).
 
diff --git a/doc/lispref/customize.texi b/doc/lispref/customize.texi
index e9260309057..e895fe34e53 100644
--- a/doc/lispref/customize.texi
+++ b/doc/lispref/customize.texi
@@ -1428,6 +1428,17 @@ loaded into Emacs, whether or not the theme is enabled).  Otherwise,
 it returns @code{nil}.
 @end defun
 
+@defvar custom-known-themes
+The value of this variable is a list of themes loaded into Emacs.
+Each theme is represented by a Lisp symbol (the theme name).  The
+default value of this variable is a list containing two ``dummy''
+themes: @code{(user changed)}.  The @code{changed} theme stores
+settings made before any Custom themes are applied (e.g., variables
+set outside of Customize).  The @code{user} theme stores settings the
+user has customized and saved.  Any additional themes declared with
+the @code{deftheme} macro are added to the front of this list.
+@end defvar
+
 @deffn Command load-theme theme &optional no-confirm no-enable
 This function loads the Custom theme named @var{theme} from its source
 file, looking for the source file in the directories specified by the