Based on recent CRs and feedback I've redesigned the recently updated Stable interface policy.

Old: https://www.mediawiki.org/w/index.php?title=Stable_interface_policy&oldi...

New: https://www.mediawiki.org/wiki/User:Krinkle/Stable_interface_policy

I hope this is more approachable and easier to navigate from the various perspectives and use cases where you might need it (e.g. when reviewing code, writing code in core, writing code in an extension, planning out the deprecation roadmap for a feature, etc.).

This page is currently a draft because during the rewrite I noticed a few minor inconsistencies and open questions in the nominal text. These are being fleshed out through an RFC at < https://phabricator.wikimedia.org/T255803%3E. Once we've decided on those details, I'll publish the new design to the canonical page.

-- Timo