NVAPI is NVIDIA's core software development kit that allows direct access to NVIDIA GPUs and drivers on supported platforms, and it's now been put up on GitHub.
Without any additional commit messages except the repository description, Nvidia posted the source code for its Developer Kit tool on Github under the NVIDIA Corporation organization umbrella.
I believe this is something that was previously fairly widely available to businesses under NDA.
If I remember correctly, it’s a bunch of management and configuration settings for GPUs besides core graphics and computer functions.