Modding, copyright, and related issues.

As far as I understand, they expanded the Lua capabilities in the game by modifying the executable file, and I tend to agree with Gerter that they only have fragments of code.

No, the modifications are still at the level of changing some variables, like how the number of possible slots for creatures was increased for NCF. As for the source code, the situation is extremely unclear... it seems like they have it, but those who are actually working on the mod only receive small parts of the code from the person who owns it. There are definitely no new Lua functions yet, but they might appear if what's in my screenshot is completed.