Few emulators today are proprietary. The vast majority are open source emulators with native support for Linux. However, there is a strange case called Cemu. An emulator for the Nintendo Wii U console that is still closed source, and does not have a port for GNU/Linux distros.
The good news is that it will no longer be strange, since there is a roadmap that has marked when the official open source version. This will attract many interested in the code, who will be able to contribute or create their own improved forks. And if this sounds like good news to you, there is better news…
And it is that they have also marked another objective in their roadmap, and that is create a native port for Linux. So the Wii U emulator will also be compatible with the distros, so you can enjoy all the video games of this Nintendo console. In fact, there is a parallel project that is ongoing, although it is going a bit slow, since it was a low priority.
At the moment, according to the developer, the project is already at 70%, so it has little left to finish, and perhaps with the opening of the code it will speed up even more. This will also be very positive looking at Valve's console, Steam Deck, as it would also have support for SteamOS 3 (Arch Linux).
As for the dates, it is planned that in 2022 be when it becomes open source, to have an open-source Cemu available. Although before that they will have to restructure the code of this Wii U emulator, rewrite some parts in C++ 20/23 that are now in C, move from Visual Studio to cmake (something that may give way to compatibility with more operating systems), etc.
Therefore, you are closer to a wii u emulator for Linux, with all this that is cooking with Cemu...
Roadmap of the Cemu project – Official Web