Picoprobe allows a Pico / RP2040 to be used as USB -> SWD and UART bridge. This means it can be used as a debugger and serial console for another Pico.
The xiao branch of this fork ports the Picoprobe firmware to Seeed Xiao board.
Differences:
because the xiao doesn't break out GP4 and GP5, the UART settings are moved to GP0 and GP1:
#define PICOPROBE_UART_TX 0
#define PICOPROBE_UART_RX 1
#define PICOPROBE_UART_INTERFACE uart0
the board is set to XIAO
set(PICO_BOARD seeed_xiao_rp2040)
Picoprobe documentation can be found in the Pico Getting Started Guide. See "Appendix A: Using Picoprobe".