Often when things like this happen there's a large conspiracy at play in some peoples minds, "Apple deliberately left a security vulnerability". But it falls apart pretty quickly, it's in an open sourced package, so the assumption is someone is eventually going to see it, so it's not going to remain a secret and thus is useless as a stealth backdoor.
The likelihood is pretty simple, someone fucked up. On a potentially huge level, but a fuck up none the less. These things do unfortunately happen, and no doubt it'll prompt an internal review of their change management process, and their build chain, and what they can do to isolate issues like this in the future.
The likelihood is pretty simple, someone fucked up. On a potentially huge level, but a fuck up none the less. These things do unfortunately happen, and no doubt it'll prompt an internal review of their change management process, and their build chain, and what they can do to isolate issues like this in the future.