By-product meal
Rendered animal parts other than skeletal muscle — organs, mostly — cooked down and dried into a concentrated protein powder.
Meal means the water and most of the fat have been cooked out, so what remains is dense protein by weight. By-product means the parts are not the muscle cuts people buy: liver, spleen, kidney, lung. Under US rules the named category excludes hair, horn, hide and manure, which is not the reassurance the marketing implies but is worth knowing.
Nutritionally the category is wide rather than bad. Organ meat is more nutrient-dense than muscle, and a wild cat eats the organs first. The real problem is that the label tells you the category and not the consistency, so a by-product meal from a named species is a more informative line than a generic one.