documentation about the code

[flueg]

Is there a summary about which files cover which functionalities somewhere? I'm not really a programmer so I may be missing something obvious

[jpeg]

There isn't, but in general the file names should give you an idea of what they contain. The less obvious abbreviations are probably "ng" for "new game" and "l_" for lua-related stuff. Otherwise, there's "dbg" for debug mode, "wiz" for wizard mode, "dgn" for dungeon (a.k.a. level generation, also "map") and "spl" for spells. Some of the older files also contain a very brief description in the top comment at the top of the file.

If you're looking for something specific, it's probably best to just ask.