Please take a moment and read the ingredient label on your cat food. First, know that ingredients are listed in order of amount of content (first item is the highest content.) Many cat (and dog) foods contain "meat by-products". By-products in pet food is a controversial subject. It's a complicated subject and not all by-products are bad for your cat.
Let's begin by looking at the facts. Animal by-products are what's left of a slaughtered animal after the parts intended for human consumption have been removed. This meat processing scrap includes waste material such as: feet, backs, livers, lungs, heads, brains, spleen, frames, kidneys, stomachs, intestines, and undevloped eggs. Gibles (livers, hearts, gizzards and necks) as well as other organs can still be sold as edible meats as they are - or as ingredients used to make hot dogs, bologna and sausage.
When something is labeled “meat by-product” (versus chicken by-product, or other specifically listed species) there’s no way to know what type of animal provided the meat; it could be from zoo animals or roadkill or even euthanized animals from shelters. You may have read about the dog who died after eating canned dog food that was found to have traces of pentobarbital (the lethal drug most commonly used for euthanasia of dogs, cats and horses.) USA Today reports "Some pet food companies buy raw goods from rendering facilities that process animals euthanized at animal shelters. That means that some pet food is made from a variety of meats that humans wouldn’t eat, including diseased livestock and cats and dogs containing lethal doses of sodium pentobarbital."
The reason pet food companies use by-products is because it's much cheaper than pure meat. You can read more from Halo Pets and visit this link: https://halopets.com/whole-meat-vs-meat-mealGraphic below from Halo Pets.