It just sends 12 V without negotiation.
Of course that's unacceptable and dangerous. But Fungus ended up with a generic quote about USB-C and 12V which is, at least, misleading.
I assumed people would have read the post a couple above mine.
Here's the pic, in case anybody else was confused:
12V directly into a USB connector. No data lines, no negotiation.
(not to mention what looks like a simple linear regulator)
I assume the Export versions won't have that.