Currently Alaric has only one bitbase (a complete database of an endgame). The bitbase kpk.dat that you you will get when you download Alaric covers the endgame with King and pawn versus King. It contains one bit for each possible position with '0' for draw and '1' for win - the only 2 results possible in this endgame. That gives about 120000 positions when I use mirroring and some other tricks to keep the size down. Gives about 44 Kb.
I tested a new technique where I combine chess knowledge and trees for the same endgame. Now I need only 4 Kb and it is complete, that is all possible positions are covered by these 4 Kb. I will test also K, R, P vs K, R to see what can be done. If that works out I will complete all 3- and 4-men endgames with the same technique.
5-men? Well let's see how this works out first...
It is quite a manual task to identify what kind of knowledge to use and how to represent it.
My first intention to write a bitbase generator and compress the bitbases as much as possible is somewhat changed. Look here.