Thanks, JonHeld, much appreciated.
For posterity, and as an explainer for anyone looking for this information in the future... You have to remove the dead pedal (single bolt at the base, visible), and then pull the entire kick plate trim off the left side of the driver's side footwell, which goes all the way along the doorsill. It's easy, just get something under the plastic sill and carefully pull it up - I think there's three clips that will release. The FSM shows a bolt up front of that trim piece holding it in place, but that seems to have been lost to history in my rig. Removing the trim panel will allow you to see the "R/B No. 1" from the image posted above. It's oriented like that, so the flasher relay is all the way to the front of the car on the top. In mine, there are a whole bunch of bundled wires sitting in front of it which I'll have to move out of the way and get past to pull out the old relay and plug in the new one. I haven't done it yet, since I haven't received the new relay yet, but it seems pretty easy.
For another dumb question - any trick to pulling out the relay? It really just looks like a plug to me, so my first approach will be to simply pull on it.
