[cmgriffing]

I think a baseline spec would be really useful.

I like to think of it like the unist ecosystem for ASTs. Unist provides a baseline spec that compatible tools can use to comb an AST. Then, specific AST tools like hast for HTML or sast for CSS/SCSS can add their own metadata on top.

I'm imagining an ecosystem of "adapters" that would help you translate some of the metadata across providers.