Tested with HTC Vive. Based on Unity.
After loading the Unity project, you need to manually import the VRTK toolkit and SteamVR. Copy them to these paths:
Unity\Assets\Lib\SteamVR
Unity\Assets\Lib\VRTK
The Unity project works like a client. It connects to a Python server which you must launch first, on a possibly different machine, not necessarily running Windows. See the instructions in Server/README.
Finally, the address that the Unity client connects to is hard-wired for now in the "Main Object" in the scene (fix Base Url, the first property in the inspector). It is not 127.0.0.1 because I run the server on another Linux machine.
Files in Server/ contain a bit of code directly copied from the Quake source code, which is available as GPL. So all the code in Server/ is also covered by the GPL license. Files in Unity/ should be free of such code and is thus covered by the more permissive MIT license.