Yep, the Microsoft WMR OpenXR bits are purely for WMR devices. The way to think of it is that the only reason WMR headsets like the Odyssey and Reverb could use the SteamVR API was that the app ‘WMR for SteamVR’ essentially ‘fakes’ that they are true SteamVR (nee OpenVR) devices, like the Index.
OpenXR is a common VR API, where each platform vendor supplies an implementation. The advantage is the game developer just has to use the one API now. Here’s the marketing slide:
On the right of the diagram you can see all the games developers can now use a single ‘Application Interface’, so that’s good. Beneath that each VR platform vendor supplies a ‘Device Plugin Interface’ for their runtime, so we get one from Valve, Oculus and Microsoft. Beneath that is the underlying device drives of the headset vendors.
So the only thing to remember on the above diagram is that the ‘Windows Mixed Reality’ (WMR) logo also has a compatibility app to ‘fake’ being a ‘SteamVR’ device, hence why things like DCS and IL-2 that only supported either Oculus or SteamVR could be used on WMR (via the SteamVR fake out). It’s also why we can switch between the Valve OpenXR runtime and the Microsoft OpenXR runtime (because WMR can fake being a SteamVR device).
OpenXR hopefully will help VR adoption, as just the one API now. MSFS is pretty much the only OpenXR title out there, so we’ll have to see if other sims bother to change over (they don’t need to of course, the old stuff isn’t going anyway).