A bolt ladder of truly manky 1960s (or older?) compression bolts, most of which are hanging out of the rock by quite a lot leads to some fixed gear that has "been there forever". A fixed nut, the only good piece of fixed gear on the route, leads to the only placement on the route (small gear) and a ledge up and right. The bolt ladder continues to the top but a nice anchor exists on the ledge before these.
The climb is overhanging so is good practice, obviously, for overhanging aid.
Walk off back.
The thumb is the overhanging pillar near the top, and to the left of the left climber's trail which is a separate formation from the Main Wall. The climb follows up the rusty bolt ladder on the overhanging face.
Lots of fixed bolts / rivets / other assorted fixed aid gear. Part of the thrill is how old the gear is but then the FA had quite a safe journey on their then new bolts and pitons. Some may complain if any of this was replaced but I would not be one of those people. Some day it will be a necessity.
Bring lots of quickdraws and some nuts and tieoffs for the hangerless bolt studs plus whatever else it looks like you will want.