I got a couple of Breakout UCM board. I’m bit amazed to read:
The Breakout Board also provides a USB connector for connecting to a host computer. It does not, however, have a 3.3 volt regulator. 5 volts from the USB connector is available on a pad on the board (5V USB). You can wire your own regulator between this pad and the 3V3 pad to power this board over USB. These pads and a ground (GND) pad are conveniently located in close proximity at one corner of the board (see picture below).
for a € 44 option (the same price as a Raspberry 3+) it doesn’t supply neither a simple regulator for 3.3V rail !.
I’m lucky enough to have old G400D Hdr boards…