Off-Road Assist is designed to provide overall improvements when driving off-road. In addition to allowing the wheels to spin, Off-Road Assist balances the torque between the front and rear motors to optimize traction. Off-Road Assist improves traction on rough and soft
surfaces where one side of the vehicle may lose traction while the other side still has traction. When Off-Road Assist is on, the accelerator pedal provides more gradual torque, which is useful for crawling at low speeds (for example, over rocky surfaces).
Heat pump confirmed on page 131:
"Model Y uses a heat pump to maximize efficiency; therefore, your air conditioning compressor and external fan may run and make noise even when the outside temperature is cold and your vehicle is heating or supercharging."
Wait, I thought the Model 3 uses a heat pump too? No?