I was trying to make a little WebXR html5 game here: https://my2iu.itch.io/skip-rope-vr
But the VR functionality doesn't work on itch. I think WebXR games need itch to add an extra tag to the iframe of the game to allow it to enable VR functionality, possibly this one:
<iframe allow="xr-spatial-tracking"></iframe>
or it might be a feature policy that has to be added when serving the main page, not too sure.