As part of T71997, the url used for RFC magic links changed recently: 8ca390fe6c4f82e7960a84301101a8391292d727 per https://meta.wikimedia.org/wiki/Talk:Interwiki_map/Archives/2024#RFC
This required patches in Parsoid (https://gerrit.wikimedia.org/r/c/mediawiki/services/parsoid/+/1107966 ) to both change the URL used for magic links as well as to ensure backward compatibilty with edit stash contents which still used the older URL.
This task is to manage and eventually remove this back compat code. We don't have a specific policy for edit stash compatibility, but https://www.mediawiki.org/wiki/Manual:Parser_cache/Serialization_compatibility and our general LTS upgrade compatibility suggest that we need to leave the backward compatibility in for a full LTS cycle. (Edit stash contents are populated from the parser cache, so parser cache compatibility requirements imply stash requirements.)
One option is to backport the URL changes (and the back compat code) to the recently-released 1.43 LTS, which would allow the back compatibility code to be removed from production (and 1.44) as soon as the parser cache expires (14 days at the moment, I think) + the edit stash expiration (1 day, I think).
Otherwise we can't remove the back compat code until MW 1.48, the version *after* the next LTS version (1.47) which will have the URL change.