Contains aomxmod.exe and barlist.txt, which give AoM the ability to load additional .bar files (intended for handling mods as a single file). Also included is barbuild.exe, to simplify the construction of new .bar files.
For more detailed information, see AoMPlayer000's guide in the modding forum at http://aom.heavengames.com/cgi-bin/forums/display.cgi?action=ct&f=19,20347,0,10