My boards were labeled as made by "cuiisw" in the original AliExpress listing. I am now learning that there is little if any uniformity among the various black pill boards. My boards have 38 pins (19 on a side). This gives room for mounting holes in the corners which I like very much.
Other black pill boards have 40 pins on a side, no mounting holes, and the SWD connector is not reversed as it is on mine. These are not major changes, but do need to be taken note of.
It is important thing to note that the SWD connector has the pins reversed compared to a blue pill board. So if you just hook up your ST-Link without paying attention, power and ground are reversed and you just wasted $5.00. I am proud to say I did not do this -- yet!. I am probably going to put a colored dot next to the +3.3 side of the connector on my boards as a reminder, and will do my best to avoid blowing up any boards in the future. This is a real risk given that I work with both blue and black pill boards.
Tom's Computer Info / firstname.lastname@example.org