According to an official statement on Ryujinx’s Discord server, developer gdkchan was contacted by Nintendo and they were offered an agreement to stop working on the emulator project, and while the agreement wasn’t confirmed yet, the organization has been entirely removed.
C&Ds are generally just threats to take someone to court. They aren’t themselves enforceable.
Even I can send C&Ds if I want but I don’t have anything to back them up with. Nintendo on the other hand absolutely does.
By “enforceable,” I meant, “the reasonable legal means to follow up”.