We have the identification-request tag, clearly for identification requests.
Questions which ask for help in identifying an anime, manga, or character by description, specific elements (like a character or song), or with screenshots should be tagged with this tag.
This tag should not be used for a group of animes (Example: "What animes have red-haired characters?"). Such questions are too broad and are not wanted on anime.SE.
It seems pretty clear that it should be only for identifying a particular series (anime or manga, though I'd argue light novels, visual novels, and any series in scope can go here too). However, I've seen this tag used on music requests, including this question, and was edited into this one as well. It's also been incorrectly added to questions about identifying components of a series.
What types of identifications fall under this tag, and how should we define it? Also: should we broaden it, or leave it as-is?