Add @since tags to some (not all yet) public API functions, to document in which release they were added (and/or in which release there were API changes). Document the @since usage in HACKING. Also, add Doxygen docs for the functions in version.c.
These short descriptions are shown in the "Files" section of the Doxygen output.
Also, add an overview mini-section to the main page instead.
Uwe Hermann