If they do one of those, it will be obvious it happened, because people can at least reverse engineer iOS and see that it’s different.
If they add some new hashes I presume that would be harder to spot and isn’t going to be advertised
If they add some new hashes I presume that would be harder to spot and isn’t going to be advertised
A few bytes changed in a binary blob that would enable a backdoor would be almost impossible to detect.