- "Customize all user option variables whose default values changed recently.
-This means, in other words, variables and groups defined with a `:version'
-option."
+ "Customize all user option variables changed in Emacs itself.
+This includes new user option variables and faces, and new
+customization groups, as well as older options and faces whose default
+values have changed since the previous major Emacs release.
+
+With argument SINCE-VERSION (a string), customize all user option
+variables that were added (or their meanings were changed) since that
+version."
+