i looked at the schematic, the fmant comes out of the headphne amplifier. it is hooked up to the same lines as headphone output transformer. i dont know the model no of headphone amplifier and BOB. if we can find datasheets for the headphone amp it would be helpful. Bob it seems like is the WLAN/BT chip some of them support FM output.

Interesting, in the schematic, there is no picture of the Top. Only the bottom.