What would a fediverse "governance" body look like?

This reply is related to an off-topic comment in What would an ideal fediverse organization do?

A formal organization can have a variety of structures and you can assign roles and power in a variety of ways. If you structure it in such a way where the working groups are autonomous and members have a way of influencing the working groups, then you don’t have the top down hierarchy that you describe. Even if you have someone at the top, you can give them little actual power.