Looks like owner of Ryujinx changed and now is developed by someone else? The top contributor for this is gdkchan, the previous owner and main developer. So this is not simply a fork, but changing ownership of the original repository. Is that right?
It makes sense, because what happened previously is that gdkchan got a message (or visit) from Nintendo to stop working on the emulator. That’s all. There was no cease and desist to the entire project, or anything like that (unlike with Yuzu).
I thought the contributors list would be reset when uploading to a new location. At least that’s for forks, so that was my assumption without checking actually. I mean for the forks, gdkchan still have the commit history too, like any other contributor.
I think you are right: https://docs.github.com/en/repositories/creating-and-managing-repositories/transferring-a-repository
And looking in the list of forks, the oldest one seem to be 1 month old or so.