A sad day for emulation and open source advocates, and a reminder that Nintendo can and will destroy you if they see fit.
Hopefully their works will live in the saved repos just as ReVanced was able to live on after YouTube shut the original project down.
It would be better to “git clone” a repo under threat of removal than fork it in Github. That way an entire copy of its history is preserved. It’s possible the forks still exist for now, even if Yuzu removes their official repo, but if Nintendo serves Github the legal paperwork then the forks will get blasted.
That said if someone clones the repo, they probably ought to think twice before putting it back in the cloud without sanitizing / reconstructing the branches & history absent of the bits that got Yuzu into trouble in the first place.