The plane added callback is never executed, even though planes are detected by the underlying WebXR API and are visible when enabling the WebXR Debug toggle.
I can’t comment about iOS, as it has no official webxr support and I don’t have an iphone to test with. I answered in a different thread, but here is t summary -
This demo requires hit-test, plane detection and anchors. and if they are not available, it will fail silently (on certain cases the XR session will not even initialize).