Baba Is You saved game
From Just Solve the File Format Problem
Baba is You saved game files save various pieces of metadata about levelpacks that are played, most notably of which the bonuses, level wins, and world clears of each levelpack. The main four files used by the game are ba.ba, 0ba.ba, 1ba.ba, and 2ba.ba, although with a bit of hacking, the game can load 3ba.ba and beyond.