There is a wiki page regarding Windows: https://github.com/doitsujin/dxvk/wiki/Windows
It is not officially supported on Windows, so that's probably why it isn't in the repo's description.
As said above the officially targeted platform is Linux and Windows is more of a convenient side effect that the devs try not to outright break. Windows have a page in the wiki targeted at people with issues since it is known that dxvk see a lot of usage there too.
It's also best to keep in mind that outside of several specific cases/games, you are likely to get better performance by not using dxvk on Windows - it's certainly not the silver bullet some people make it out to be.
Nothing extracted yet.
The page says "Vulkan-based implementation of D3D8, 9, 10 and 11 for Linux / Wine" but it can also be used for Windows, could that be added as many users on Windows would think they aren't able to use it.