>>etc-ho+(OP)
When I saw "supes" in the headline I thought it meant superintendants, as in people in charge of a school system.
Here it means members of the county board of supervisors. If you live in a place where that's not a thing, it's very similar to a city council or county commissioners in many other US places.
>>hoistb+Sc
The City and County of San Francisco has a unique unitary government, where the citizens in my experience think of the supervisors as city supervisors, not county supervisors, even if both or either might be technically accurate.