currently it looks to me like Chrome 83, does not support any VR experience although HTC Vive is connected (SteamVR 1.9.16 installed). SteamVR, when started manually, also finds the headset, controllers and base station.
https://threejs.org/examples/?q=webxr#webxr_vr_ballshooter
Any VR Example states "VR not supported"
digging arround a bit, the navigator describes the "immersive-vr" session not to be available. Promise response of code below is: false

navigator.xr.isSessionSupported('immersive-vr').then((issupported) => {console.log(issupported)})

The previous flags of Chrome (83.0.4103.61) linked to WebXR are not available any more.
Any ideas what I am doing wrong?

EDIT:

navigator.xr.requestSession( 'immersive-vr', { optionalFeatures: [ 'local-floor', 'bounded-floor' ] } ).then( (session) => console.log(session) );

Gives: Uncaught (in promise) DOMException: The specified session configuration is not supported.