https://github.com/metabrainz/musicbrainz-server/blob/ad6f5aa090bc25fecea48b4530e40625dc5c9014/root/components/common-macros.tt#L756 is getting a class "iTunes" - but our class here is "itunes": https://github.com/metabrainz/musicbrainz-server/blob/72e13b6fccfbb103c48bc5a0a4b570d2026cdd53/root/static/styles/favicons.less#L42 - so it doesn't display. Unsure if the preferred fix is just to change favicons.less to "iTunes", or fixing the reason it gets "iTunes" in the first place.