Supplies in rooms and closets new construction

Did a new construction and observed a supply in 1 small closet and none for 3 others that were larger walk-in closets. I've been researching my books but don't see if it is required to have them in closets or if it's by sq footage in a room. Does anybody have a reference? I couldn't find a building reference, I did see that habitable rooms should have a heating/cooling source. I referred this back to the builder for verification of supply sources. The other new construction developments in my area have them in the closets as well.

Thank you in advance.

You are correct, heat supply is required by codes in habitable rooms only. However, in cold climates it's customary to have heat in walk-ins and bathrooms. I'd sure want heat in a walk in closet!