Feedback Where is XR documentation?!

/rantModeOn
The documentation is very, very, VERY poor.
For example.
I want to get XR display parameters.
The search gives me this: https://docs.unity3d.com/ScriptReference/XR.XRDisplaySubsystem.XRRenderParameter.html
I can't even figure out how to use this class (XRRenderParameter). No links, no examples, nothing!

Another good example:
XRDisplaySubsystem
https://docs.unity3d.com/ScriptReference/XR.XRDisplaySubsystem.html
But how I can access this class object?
I found accidentally in othe topic, that the right way to get it, is this:
SubsystemManager.GetSubsystems()
There is absolutely no references or links to SubsytemsManager on the page. How I suppose to know about SubsystemManager?!
/rantModeOff

 

Its true!