How would oversight work in an App Store environment? I'm assuming it would be far too tedious for a human to review each line of code. Millions of apps, a coup

How would oversight work in an App Store environment? I'm assuming it would be far too tedious for a human to review each line of code. Millions of apps, a couple hundred people. Not happening. Being the "same type of malware the CIA developed" could we assume that Apple is allowing this type of backdoor through?