13.3.2.1.6 Universal Program Debug Interface (UPDI) Reset
The UPDI contains a separate Reset source that is used to reset the device during external programming and debugging. The Reset source is accessible only from external debuggers and programmers. All logic is reset on UPDI Reset, except the UPDI itself and BOD configuration. All fuses are reloaded after the Reset is released. See UPDI chapter on how to generate a UPDI Reset request.