I haven't had much time to poke at this, but there was an "editor" user group at test.wikipedia.org (testwiki) at some point. It seems to no longer be available at [[testwiki:Special:UserRights/Az1568]], but it still has members (cf. [[testwiki:Special:ListUsers/Az1568]]). This may require a steward or a clever API user or a sysadmin to empty the user group, assuming it should be empty.
Version: wmf-deployment
Severity: normal