You can check it yourself: https://wiki.wireshark.org/CaptureSetup/USB
but I think there is nothing intresting, I think this is a "low level" updater or repair that tries to fix the system if you can't boot the normal recovery menu (because broken sysmodules ?)
Downgrading certainly not, but Kate's confirmed that computers have access to the NAND over USB in that she's recommended we have a USB A to C cable to back it up before we mod itWould I be wrong to assume that having a console that connects to USB would show a lot of hacking potential compared to something like the 3DS that has no USB capabilities. At least not out of the box like the Switch does. Maybe one day we could plug our Switches up to a computer and do such tasks as downgrading, or injecting custom themes, or movies... I M A G I N A T I O N~