NVIDIA sneakily put out a little open source release recently, with a part of the NVAPI SDK now under the MIT license.
This was mentioned by the crew working on the DXVK translation layer in the VKx Discord, who sent along word to me as well. NVAPI is NVIDIA's core software development kit that allows direct access to NVIDIA GPUs and drivers on all Windows platforms.
Now, that doesn't sound interesting for Linux obviously but here's why this actually is important: in the NVAPI Open Source SDK, it directly mentions that the contained "nvapi.h" file that's now provided under the MIT license was done to enable "open source re-implementations of NVAPI for Windows emulation environments"—so the Wine and Proton compatibility layers are what they're getting at without naming them directly.
What's the issue with it then, why did this need to be done? Well, DXVK at times has to work around the NVAPI and it ends up spoofing an AMD GPU for some titles to do this, otherwise they just don't work on Linux with Wine / Proton. Speaking briefly to Philip Rebohle, creator of DXVK, they mentioned to me that there's going to be things that aren't possible to implement but it does now give them something to work with.
It's just another small piece of a much larger puzzle of getting Windows games running on Linux.