Back in July 2020, NVIDIA announced the open source release of various parts of the NVAPI interface to help "Windows emulation environments" and they've now produced a much newer version.
What exactly is this? As their documentation from the release states:
NVAPI is NVIDIA Corporation's core software development kit that allows access to NVIDIA GPUs and drivers on all Windows platforms. NVAPI provides support for categories of operations that range beyond the scope of those found in familiar graphics APIs such as DirectX and OpenGL.
This release contains a version of nvapi.h, provided under MIT license, to enable open source re-implementations of NVAPI for Windows emulation environments.
An NVIDIA developer sent word about the update, which expands the support across a ton more Functions, Structures, Enums and so on. For regular gamers, it doesn't mean all that much. However, for people working on the DXVK / VKD3D-Proton translation layers, this can help. One possible use case is so the likes of DXVK might not have to keep spoofing being an AMD GPU for certain games to work around issues with the NVAPI.
Just another small piece of a larger puzzle involving getting Windows games running on Linux nicely with Steam Play Proton.