Ok here it is. however, I think because there's no XMP in the web code I can't quite get mine to work https://developer.apple.com/wwdc24/10065

I am also looking for this, as it would be delightful to share spatial videos with other AVP users without being forced to go into an app or FaceTime. It's basically right and left images if you see the Apple code for creating spatial videos - but I don't have enough JS or webXR knowledge to understand how to do it. I'll try to figure this out and send links back to your post.