@sun4all Yeah, you can edit it if you want. I don’t mind people modifying it for their own setups, just give credit if you release a modified version publicly.
For editing the loot pool / box values, the logic is inside the common_zombie_patch.ff, so it is not as simple as editing a normal config file. You would need to extract/decompile the relevant GSC, edit the weapon order / box logic, then rebuild or patch the .ff again. Most of the current logic is basically map checks + forced weapon returns for the Mystery Box.
About adding wonder weapons to maps where they are not normally available: in my opinion, that is much harder to do properly and stable.
If the weapon is not loaded/preloaded by that map, simply forcing the weapon name can cause issues like invisible weapons, the box giving nothing, crashes, missing sounds, missing FX, or broken animations. That is basically what happened with the Verrückt/Waffe issue.
To do it properly, you would likely need to port or load all the required assets for that weapon, such as:
weapon files
models
animations
sounds
FX
scripts
precache/zone references
So adding something like Scavenger, Baby Gun or Wave Gun to maps where they do not normally exist is probably possible, but I would not call it easy or guaranteed stable. It is more of a proper weapon porting/custom mod project than a simple loot pool edit.