Does WebXR support for rendering webpages *plural*?

Is the ability to load multiple webpages a part of the core design goals of
WebXR?

This could mean loading two AR pages at once, loading AR in VR, or even two
VR pages.

I've talked with the folks working on OpenXR and this isn't on their
current agenda. However, the web is made for dynamic content like this.

WebVR wasn't at all set up with this in mind. I've looked at the compositor
for WebXR but it isn't clear to me the scope it is expected to be used in
https://immersive-web.github.io/webxr/spec/latest/#compositor Is there are
good place that talks about this?

This is a picture of the sort of multi webpage systems I am talking about
but made with the Window's compositor: https://i.imgur.com/3Ckom1w.jpg

--Brett