Endmyopia:Jake Steiner and Janitor
You can find the Jake Steiner and Janitor user rights in Special:ListGroupRights. They are both identical in function and only allow these rights:
- Edit all user rights (userrights)
- Unblock oneself (unblockself)
- Enable two factor authentication (oathauth-enable)
Are they some sort of tier above bureaucrat? Not really, bureaucrats are definitely the 'god editors'.
Jake Steiner user right
Jake Steiner user is... User:Imperial-beard. He has the Jake Steiner userright mainly for vanity reasons, and so nobody comes along and tries to spoof him (unlikely). Jake also has the 'Janitor' userright.
Janitor user right
The Janitor is... User:NottNott, guy who originally started the wiki thing off. He has the Janitor userright.
Why more rights?
Bureaucrats can do literally everything on the wiki, except for assigning these two rights (can assign all other rights, and do everything else ever). The idea is that in the extremely, undeniably unlikely event a bureaucrat went rogue, users with the Jake Steiner and Janitor userright can fix the problem. Otherwise, the bureaucrat can remove userrights from everybody and then someone has to dig around in a config file, which isn't 100% practical to solving the problem quickly. The difference in response time could cause orders of magnitude greater work to clean up things in the event a bureaucrat went mad with power 
Another is for vanity reasons, similar to the Founder user right on Wikipedia for Jimmy Wales. It pays a little respect to the creator who has given out thousands of great resources for a long time now and has gone seriously out of pocket at times to bring vision improvement to a lot of people. And to some scruffy young adult who knows a thing or two about wikis.