The onboard STM32F407 has a transceiver, if you look at the schematics.
but the transceiver isn’t connected to the “Pi”, it’s connected to the STM32
So if we want to connect a toolhead board, we are supposed to use this connector (make sense) and makermase said the THR36/42 will connect through it, so this way we should be able to use sth. like the EBB36/42 too.