The answer seems to be cheap-o no-seal cartridge bearings pressed in to the frame. The steerer tube is 1.125″ straight, and the OD of the bearing is 1.75″. They needed a tiny bit of persuasion to come out of the frame:
Image of the bearing.
The angled surface doesn’t seem to be important in terms of the mechanical fit between bearing and frame, the inside of the headtube is machined to about 9.5mm deep and the bearing only contacts about 3.4mm of that surface. The bearings seem to be identical top and bottom, and do not have any numbers etched on them.
I’ve had the Wazoo since early March, and I’ve only done about 250 miles on it. It’s still on the poor side for the headset bearings to be goosed so soon.
I’m off the LBS to see about some bearings which keep water out.