--- a/mercurial/help/config.txt	Wed Nov 12 23:47:25 2014 -0800
+++ b/mercurial/help/config.txt	Thu Nov 13 00:08:44 2014 -0800
@@ -547,6 +547,9 @@
 ``nodates``
     Don't include dates in diff headers.
 
+``noprefix``
+    Omit 'a/' and 'b/' prefixes from filenames. Ignored in plain mode.
+
 ``showfunc``
     Show which function each change is in.