https://beta.musicbrainz.org/user/Deleted%20Editor%20%23346478/subscribers

We remove artist and label subscriptions when artists and labels are deleted (we could but don't end up subscribed to "deleted artist #mbidhere"...), so I'm not sure why the same doesn't happen for editors. Sure, the editors aren't truly removed, but they've disassociated themselves from their account and can no longer log in nor enter edits...