+@c `Extending' was born 2004-03-07 with this commit:
+@c * Documentation/user/changing-defaults.itely (Changing defaults):
+@c author: Han-Wen Nienhuys
+@c commit: c53d0cabdf9361e448cdd02a338aa5d696f4f466
+@c file: Documentation/user/programming-interface.itely
+