Current text: > In cases where it might be mutually beneficial for wiki-hosted code developers and MediaWiki developers to share code, for example for performance reasons, this MUST be documented in the source-controlled code using the @public and @since keywords and linking to the on-wiki discussion. HTML classes that do wish to be considered stable MUST add an inline comment indicating in which MediaWiki version they were introduced using the @since annotation and must follow the deprecation process in the relevant section below.
In https://www.mediawiki.org/w/index.php?title=Topic:Xn1201q2fbyyb7wj&topic_showPostId=xn12lkeg09wg4zni#flow-post-xn12lkeg09wg4zni @tgr rightly suggests this is hard to document and suggests that instead we could make the class itself declare that it is stable.
I like the idea but wanted to run this by a few people before adding. I'm also not sure if we have any classes that would want to behave in this way so we may also want to evaluate dropping this in a future version of the policy.