BEHAVIOR

From ZDoom Wiki

BEHAVIOR is the lump that contains a map's scripts in compiled form. If your level uses any scripting at all, it is polite to also provide your scripts' source in the SCRIPTS lump (import it after the BEHAVIOR lump it corresponds to). If your resource editor takes issue with many lumps named SCRIPTS being in your wad (you should only encounter this if you have multiple scripted levels), the SCRIPTS lump can be named something like SCRIPT01, SCRIPT02, or something like that. The name of the SCRIPTS lump is not relevant to ZDoom. ZDoom does not use it, it is only a reference for other people to use to see what your level's scripts are actually doing.