The M7 (and the H7 apparently) has 5 VIAs above the USB port labeled GND, 3.3v, RST, SWD, and SWC. How are they used? Presumably GND is just an obvious ground connection. Is the 3.3v via an output “rail” to power other devices, or is it a VIN of some sort (and if so, is it really 3.3, unlike the VIN pin which is documented as 3.6V-5V?)? How does the RST VIA (“reset” I presume) work? Is it just redundant with the highest numbered pin, connecting to ground to reset the board, and otherwise not useful? What are the SWD and SWC VIAs for? I’m not familiar with that terminology and Google didn’t reveal much at a quick glance (“serial wire debug”?).
Also, if this is all documented somewhere in a manual, I’m sorry I haven’t found it yet. I’ve perused the MicroPython docs and their short sections on individual hardware (PyBoard and M7 respectively) but I’m not aware of a thorough hardware guide for the M7. Have I completely overlooked an obvious resource I should be utilizing?