doc(standard): deprecate usedBy

[bfabio]

No description provided.

[bzg]

Hi Fabio, I probably missed some previous conversation about this: why is usedBy deprecated? This is something we use in https://github.com/codegouvfr/awesome-codegouvfr/ and this is a useful information we want to promote. Is it replaced by something else?

Copying my colleague @hjonin on this.

[bfabio]

Hi @bzg, it's a proposal that has been cooking for a while now because usedBy comes with many pitfalls. I marked it as a draft while I'm writing the rationale and the various thoughts we've had over the years, so we can have a single place with all feedback we gathered.

It's not final of course, there's still the discussion and voting to be had.

While we're at it, I think we can try and vote the proposals for v0.3.1 of the Standard this month (leaving this one out if there's no clear consensus).

[bvhme]

I saw the usedBy also used in the prototype JoinUp catalogue. I like it, but understand there are some pitfalls with a key like this and that it might not completely fit the concept of the standard.