: Contains the main game engine data, textures, sounds, and the entirety of Episode 1.

The internet consensus (verified by speedrunning communities and source port developers) for a is as follows:

) contain the game’s actual assets—models, maps, and sounds—and are required for the game to run.

gfx/ – 2D assets (conback.lmp, palette.lmp) maps/ – e1m1.bsp through end.bsp progs/ – progs.dat (QuakeC bytecode) sound/ – doors, gibs, explosions (WAVs) textures/ – water, sky, lava animations