UnityEngine.Windows class is unreachable in non-Windows store setup. It should be clarified as such

I was looking for a System.IO.File documentation and stumbled upon Windows.File class. When I tried to use it, Mono came up red and said there's no such thing. Dev clarified it's only for Windows store builds. Figured it should be stated as such in the documentation.

Just take a look here
https://docs.unity3d.com/560/Documentation/ScriptReference/Windows.File.html

It doesn't really come up with any explanation if you end up trying to use it in your non-Windows store project and come up short.