It's that layer on the pig that has skin and meat held together by a layer of fat. It's seasoned and heavily salted to stay preserved and it has some of the best flavor that I've encountered in pork products. I don't eat the bits with skin, but I love chewing the flavor out of them. It's a bit leathery, but still good. I make the soup with green beans, fresh peas, carrots, pearl onions, corn, potatoes, celery, salt pork, and either pork broth thickened with flour, or water thickened with milk and flour. Pepper and occasionally something spicy to taste, and no need for more salt. My grandma used to make it with this incredibly thick, dense bread that absorbed all the juice.