Clearly made from trimmings, lots of fat and often gristle. I've gotten these packs a whole bunch of times.
They're fine, great even for a slow cooked stew. Don't bother if you're not going to slow cook these.
If used as an ingredient, say in a cheese sauce or even for cheese on toast or something then it's fine. But if you plan to just eat this as-is then I'd avoid, it's quite rubbery and plasticky.