DX of element reference attributes in HTML #10143

Hello everyone,

FYI: There is a new discussion in the HTML spec space which rhymes with
some of our discussions around MathML 4, Intent references [1][2]. Namely:

"Improve DX of element reference attributes by allowing relative references
instead of only id"
https://github.com/whatwg/html/issues/10143

The issue introduces the pain points of using global id attributes. It then
makes a case for using two mechanisms, asking for further proposals:
- relative selectors (siblings, ancestors), avoiding the need for anchoring
markup (id, arg)
- scoping guards, avoiding the risk of "global" conflicts. In this vein, we
could think of our current Intent references as scoped to an implied scope
of "current-subtree" with some extra stop conditions.

I am bringing the issue to everyone's attention in case we find it useful
to collaborate cross-group. In a perfect world we would have very similar
(if not identical) upgrades for referencing in HTML+MathML+SVG.

[1] Intent references:
https://w3c.github.io/mathml/spec.html#intent_reference
[2] sibling intent references: https://github.com/w3c/mathml/issues/402

Aside: DX (developer experience) is a more human-centric term for what I
usually call "spec ergonomics".

Greetings,
Deyan