In real - every map has such format. You can read it from file mapinfo.dat - 4 bytes starting from offset 6, re-write them in reverse order (you'll see hex value startig with 00 00), convert to decimal - voila! Here you are - 810/770/730


PS If you'll try very old maps - you'll find formats like 700/720/800

PPS Almost the same happens with files cspeech.dat - can share them between same Format same release maps (as between several releases - hardly somebody tried, however I don't see any sense doing so)