[The nebulous void latter brought into focus by the gravitational pull of a passing EVRR.]
It's held up by two screws and wall anchors. The layout's frame rests on those and the package states they should support around 60lbs. Later I'll add Ikea-style wall plates to the frame to prevent accidental falls - there have been earthquakes here that have shook things from shelves, so better safe than sorry.
At this point it's not beautiful enough to be hung in any prominent place, but once scenery dominates, and the pink and white foamy roughness of this stage is gone, it'll start to look quite acceptable.
After many tests I've started to think of the layout as having two parts: a classic dog-bone folded over on itself (marked with a solid black line in the above picture), and a valley section suitable for simple switching operations if you're so inclined. It could be wired to run with two power packs for 2-train operation. Maybe it was. Mine won't.