My understanding is that they forked it after he had a different, earlier crashout about their retroarch core and handling user support. He changed the entire license to prevent them from continuing to use his code to make a core. Then they hard forked from before the license change and made the swanstation core. So not illegal, but spiteful as all hell.

That said, forking it illegally wouldn’t be outside the realm of possibility for the retroarch devs. It’s entirely possible I don’t have accurate info on the order of events etc.

But I’ll be real, while I care about these devs as people and wish they would just get some community members to act as filters for support requests (seems to be the leading cause of dev burnout)… emulator dev drama isn’t worth getting wrapped up in.