The comments on the page are likely correct - CP10356AT. Custom asic or semi custom pd controller for nintendo that supports pd 3.0+, which includes secure vendor-defined messages

The STM32G0B0 is possible but less likely if the CP10356AT is on the pd line, and the STM could coordinate handshake message success

Another scumbag move by nintendo. I hope someone figures out a way to mimic the dock response, dumps the firmware, or emulates it. That’s beyond me but fuck them. Flood the market with $15 clone docks

Edit: Thinking more on that I will say that nintendo probably did this because of third party docks damaging switches. I repaired a bunch of switches and a common issue I would see is a blown up pi3usb chip with often pcb damage leading to pin (iirc) 5. This was caused by cheap/shitty docks feeding too much power or incorrectly negotiating power delivery. It wasnt just like cheap AliExpress docks either, nyko, insignia(best buy), etc actual name brand docks would brick your switch.

Swapping the damaged chip for a good one would make the switch boot and work normally except it would only work in handheld mode. To work in dock mode you’d have to rebuild the damaged trace. Nintendo won’t do this; they would just replace the entire board, so to them this is a very costly repair (though tbf paying a tech labor to replace a chip and rebuild a trace is costly too as it’s much more skilled labor, requires more testing, and has a much higher potential for failure after repair)

That said I still think it’s a users right to use a third party dock if they so choose. Fuck nintendo. Though nyko should be on the hook to buy you a new switch if they design a piece of shit that wrecks your switch