Confit simply means that it has been slowly cooked in its own juices and fat, rather like LynneSin's briefs on a hot, muggy day.
You can confit anything that has a lot of fat, or to which you add a lot of fat. The result is a pile of tender meat. That's it. Duck is ideal for confit, because it has a nice flavor that shines through the fact that you are basically eating fat.
Confit, owing to the fact that it is capable of elevating an otherwise tough and undesirable piece of meat (like, for example, Cali), began as a poor man's technique. It was coopted by chefs who realized they could make better cuts of meat even more flavorful. Of course, DUmmies will claim that it's all the rage in the better kitchens when in fact it's old as the hills. Sous vide cooking is currently in vogue, although it often misapplied.
All of which to say that this is just plain vanity posting by a DUmmy looking to build street cred. Odds are he really had a slice of American cheese between two pieces of white bread.