Caputo "Extra" is a flour produced with a low extraction rate.
Lower extraction rates are the whiter flours from which progressively more of the bran and germ (and thus B vitamins and iron) are excluded, down to a figure of 72% extraction, which is normal white flour. ‘Patent’ flours are of lower extraction rate, 30-50%, and so comprise mostly the endosperm of the grain.
This flour is recommended for dough with short leavening times.
Because it is lower in protein it makes a soft crumb (interior) which is more like store bought white bread or regular Italian bread. Baguettes are usually made from this type of flour. It is very much like an American all-purpose flour but "00" and Caputo quality.
Antimo Caputo 00 "Extra" originally comes from a 55 lb bag that has light or baby blue highlights on the bag, but please don't confuse this with the Pizzeria flour which is known has a darker blue bag. People on the pizza making forums have a habit of referring to the different Caputo flours by colors rather than names, which leads to endless confusion.