Earlier quoted context omitted.
Beware trying to use these on desktops with a PCIe adapter though, the adapters don't seem to break out all the correct signals, so you get USB, or PCIe, but not both.
Not so -- the for-wifi adapters (ie those with a m.2 key E) always present a single PCIe otherwise no Intel wifi card would work.
Do those also expose the USB lines on the NGFF port? I've found the PCIe-to-NGFF adapters to be PCIe-only. And I believe USB lines are required for the onboard USB JTAG to work. Am I wrong?