It does support WebXR (featured flag in VisionOS 1, by default in 2) which LOVR looks like it was using

https://github.com/bjornbytes/lovr/issues/176#issuecomment-6...

EDIT - WebXR target was removed from README in July 2023, with commit message "Don't trick people into thinking WebXR is supported right now, and spell macOS better."