Since the Oversight extension was removed from WMF projects, the oversight entry at Special:ListGroupRights is broken among other things in logs.
>>! In T109327#1626170, @Umherirrender wrote:
>>>! In T109327#1620130, @MarcoAurelio wrote:
>> If it's easy, I may be able to fix it, but I'll need guidance on what to do/which files edit. Also, new group should still be called oversight or suppresser? Best regards.
> Just add the englisch and qqq message key to the WikimediaMessages extension. It has to be oversight, because the user group was not renamed on wmf wikis.
So doing as a temporary solution until the group is renamed. I was told such rename might not be easy and take some time, so I'm working in a temporary solution for this meanwhile.