Just came across https://xrfragment.org. A philosophy and specification (RFC) on interconnecting 3D models in metaverse-like worlds. Although see their quote on metaverse below. To paraphrase from their FAQ:
Philosophy: We have plenty of wellcrafted, amazing 3D assets on the web.
What’s missing? Hyperlinked no-code storytelling.
What else is missing? adressibility of XR experiences. Less boilerplate code = productive XR design
Do ask yourself: why do Code-heavy XR applications tend to break over time due to browser/OS/dependency updates?
Solution: XR Fragments
Has anybody ever come across this idea/spec, or even played around with it? The spec has been out for almost 2 years now.
By the way, that website is really messy…
Bonus points for the metaverse answer: 
Q: How will this enable the metaverse?
A: The metaverse is a fantasy sci-fi concept from a book. XR fragments deals with real people creating 3D interlinked content & storytelling.