MD2
From Just Solve the File Format Problem
MD2 (Quake 2 model format) is a 3-D modeling format introduced in November 1997 by id Software for the Quake 2 game. It is a binary format using little endian numeric format. The later MD3 format was used in Quake 3.
Format description
(several of these are labeled 'specification', but don't seem to actually be official)