They didn’t include the keys with it, Nintendo is claiming that because the most common usecase of the software is only available with the keys, that:

“Developing or distributing software, including Yuzu, that in its ordinary course functions only when cryptographic keys are integrated without authorization, violates the Digital Millennium Copyright Act’s prohibition on trafficking in devices that circumvent effective technological measures, because the software is primarily designed for the purpose of circumventing technological measures.”

Which is a load of BS from Nintendo, what’s happening is they’re trying to get a judge to say that emulators are violating copyright, whether they provide the keys themselves, or even if the user has to get the keys from their own console. Under the logic they’re trying to use, emulators for bioses for earlier consoles would fall under this as well. They’re targeting the legal gray area to try to get rid of it.

I don’t know how well that would hold up in court, but it’s enough to bully Yuzu into a settlement and scare some other emulator devs in the process, so they got their partial victory either way.

Obligatory “I’m not a lawyer”, if I said anything wrong, someone who knows more about this stuff please correct it