They can demand whatever they want. Doesn’t mean it would hold up in court. As long as they take down the obviously infringing material, it’s really not going to be worth Disney’s time to go after them for code that’s not infringing (I suppose they may have used code from disassembled and decompiled binaries, which…

When will people learn that you gotta keep this stuff private until it’s completely done.  Then you release it into the wild and pretty much it spreads then.