This is just a minor notice to those who are interested.
Tags like character:, char:, art:, artist:, etc. tend to get added when a someone (often a new user) tries to set the tag type but adds a space after it (e.g., character: bob instead of character:bob). This tag is intended to help make this mistake more obvious for cleanup, as well as give more of a chance to correct the mistake (as opposed to cleaning them up by aliasing them to the more unhelpful invalid_tag, which tends to just get removed).
artist:, character:, and so on all imply this new tag, and the common variations have also been aliased to their respective tags (e.g., art: -> artist:).
That is all. :3
Updated by user 166084