An entity should only be linked to a Wikipedia (or Wikidata) page that is indeed for the entity in question. This follows from both https://musicbrainz.org/doc/Style/Relationships/URLs#Which_URL_to_use "The URL should still be specific to the entity being linked" (although this is mostly meant as "do not link to too wide pages) and https://musicbrainz.org/relationship/29651736-fa6d-48e4-aadc-a557c6add1cb "Points to the Wikipedia page for this artist".

This suggests that we should block linking to anchors in Wikipedia pages. Generally, this is being used to point to things like a section for a particular member of a group, or a particular album, on the page for the group as a whole. This not only goes against the previous idea of a 1:1 matching between page and entity but also causes other problems, like MBS-9463 (the abstract extracted is of course for the page, not the section linked, which does not itself have an abstract). Additionally, since sections of a page do not get Wikidata pages, anchors will in any case be lost once we finish a migration from Wikipedia to Wikidata.