What are the purpose of these FETs shown in the MPQ4230 typical application circuit?
For some PD controllers, the USB interfacing pins are low voltage pin. The FETs are added to avoid shorts to the 20V Vbus damaging the pins. Normal operation CC voltage range is 0-5V, so those FETs won’t affect normal operation, but when CC voltage on right side shorts to 20V, the IC side CC voltage is clamped.