Actually Debian's support for Quake based games and engines is excellent.
We have quakespasm (quake1 engine), darkplaces (quake2 engine) or ioquake3 (quake 3 engine). You can play Nexuiz and OpenArena with them for example. There are also tons of Doom related engines, prboom-plus etc.
I already wanted to ask you (not seriously) if we can replace some UFO code with darkplaces and simply link against this engine but I didn't want to annoy you.
how are other quake based engines doing this? or is none of these in debian?
Good question. So it seems OpenArena sorts all files in a specific order and ensures that e.g. all textures have the same crc32 value to be compatible with upstream. But the package maintainer simply provides upstream's bsp files, the same goes for Nexuiz.
I think I'm going to file some grave bugs against those packages right now....
I have to think this over. If we can't produce identical tarballs for now, I have to rely on your precompiled bsp files and I hope they will be treated like all other quake based games. At least users can compile the maps from source, if they wish, however they can't produce identical map files. I think that's a pity but won't hopefully block the inclusion of UFO:AI for Debian.