You can refer to following definition on config.h
#define APP_VBUS_SRC_FET_ON_P1() pd_internal_pfet_on(0, false)
#define APP_VBUS_SRC_FET_OFF_P1() pd_internal_pfet_off(0, false)
These definition calls pd_internal_pfet_on/off() function.
These functions are described on pdss_mx_hal.c
These functions usage can refer to pdss_hal.h or CCGx_Power_SDK_API_Guide.pdf
Thank you for presenting the material.
I will try to read and understand the "CCGx Power SDK API Guide.pdf"t.