PPM/SBus Input Pin and PWM Output Pins on Raspberry Pi?

I am trying to figure out the pins for RC PPM/SBus input and PWM outputs on Rasberry Pi 3. In Firmware/posix-configs/rpi/px4.config there are two initiallizations

navio_sysfs_rc_in start
linux_pwm_out start

and Firmware/src/drivers/linux_pwm_out/ has PCA9685 PWM driver files


but sysfs_rc_in is located at Firmware/boards/emlid/navio2/navio_sysfs_rc_in/navio_sysfs_rc_in.cpp which points to

#define RCINPUT_DEVICE_PATH_BASE “/sys/kernel/rcio/rcin”

As far as Navio2 is concerned it does not use PCA9685 PWM driver but instead use STM32F for RC input and output.
The pinout of Navio2 is a bit confusing (https://docs.emlid.com/navio2/dev/pinout/), it only mentions RCIO_SPI, RCIO_SWD, RCIO_PC10 and 11. There is no detail of the pin configuration in PXF code… at least I am not able to find one, and if that information is part of kernel module, please help me to find that.