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>. Once we've decided on those
details, I'll publish the new design to the canonical page.