Ok I finally got off my **** and checked the plans. The technical term is sheeting recess with a drip edge trim piece. It is required to get the Edge Creep Warrantee. In other words it makes sure the bottom of the building keeps the water out even if the water rises above the bottom of the sheet metal up to 3".

I have never poured a building with over 200 yards of concrete, and I have been in construction for 20 years! I am definitely keeping an eye on this one!