I like the idea. DOM morphing is nice.

I've done this previously with morphdom to AJAXify a purely server-driven backoffice system in a company.

I would love something even smaller. No `mu-` attributes (just rely on `id`, `href`, `rel`, `rev` and standard HTML semantics).

There's a nice `resource` attribute in RDFa which makes a lot of sense for these kinds of things: https://www.w3.org/TR/rdfa-lite/#h-resource

Overall, I think old 2015-era microdata like RDFa and this approach would work very well. Instead of reinventing attributes, using a standard.