The relevant spec is at Editor's Draft.

This is a silly statement. As I mentioned, it’s been working for years. MDN doesn’t mark it as experimental and tells people all browsers support it. No one is going to check whether it’s in an editor’s draft; they’ll just check MDN, see that all browsers support it, and assume it’s in the standard.

This is also racist. The actually experimental “interlinear” is needed for Taiwanese ruby. MDN says no browser supports it, but if this isn’t allowed (since ruby-position isn’t itself allowed) no one will use it and therefore no browser will be pressed to support it. Is WMF promoting bad coding practices?

In T334027#8760407, @Al12si wrote:

This is a silly statement. As I mentioned, it’s been working for years. MDN doesn’t mark it as experimental and tells people all browsers support it. No one is going to check whether it’s in an editor’s draft; they’ll just check MDN, see that all browsers support it, and assume it’s in the standard.

It has been functional in browsers for a few years and Firefox particularly for much longer.

I am not suggesting it is experimental or otherwise. I am pointing out, as is common for this codebase, whether the properties of interest are supported by a standard, and if so, what level of standardization they are at. This property is at Editor's Draft. That means it is at the beginning of the standards track.

(I wouldn't blame you for wanting the W3C to move properties faster; there are many properties that are years old besides this one that are not yet even at Candidate Recommendation or Standardized though I think it is clear they should be.)

This is also racist.

No. Consider carefully whether being polemic on this axis is going to make people agree or disagree with you.

The actually experimental “interlinear” is needed for Taiwanese ruby. MDN says no browser supports it, but if this isn’t allowed (since ruby-position isn’t itself allowed) no one will use it and therefore no browser will be pressed to support it.

Wikimedia does not need to lead in this codebase. But thank you for making clear what you are actually looking for and why.

Is WMF promoting bad coding practices?

They might be, but that is an entirely unrelated question to the rest of your commentary.