Throttle body

I was a little confused by this question until I remembered this engine had coolant lines running to the throttle body and it all came clear. You kind of answered your question already. It is to keep it warm. The throttle body in some climates can actually freeze shut so they put a coolant passage up to the body of the intake and will circulate coolant when it is cold out side so that the throttle plate inside the throttle body doesn't not have issues when it is cold.

Let me know if you need more info and we can go further. Thanks