Aliases marked as ended indicate their endedness in the JSON API (https://musicbrainz.org/ws/2/artist/e9951f2c-879d-4eb7-b209-2db29bff7f15?inc=aliases&fmt=json) but not in the XML API (https://musicbrainz.org/ws/2/artist/e9951f2c-879d-4eb7-b209-2db29bff7f15?inc=aliases).

We could add a life-span for aliases like we have for other things with dates, but that might be too big a change for ws/2. I added MBS-14052 to do this for ws/3

A reasonable way to implement this for ws/2 would probably be having an attribute ended="ended" in the same way we currently have primary="primary" for XML, which matches the ended: true and primary: true we already have for JSON.