Knowing it better than the leads isn’t that hard - they spend most their life in meetings and teaching people how to think. Knowing the code base in detail is important - but I’m certain unless you wrote it all, there are parts you don’t know. I’m sure what you do is build enough scaffold understanding and depth in the core parts you can visit any part and understand it. But I’m also certain there are parts that based on pure recall you care unaware of the details. Someone else wrote it, you haven’t had to read it yet, and thus it’s a black box. Either that or your code base is quite small relative to the team size, or the team is very unproductive. The supposition one person is fully aware of any growing code base built by a team or organization - or a monorepo being built by 10,000 developers over 15 years - is prideful. A lot of it works because it works and you accept that unless you need to inspect a part because it’s not working. Whether a machine wrote it or an intern 10 years ago did, it’s a black box until it has to not be.

Even if you did write it all, unless you are regularly in all of it (which sounds like a horrible job to me), or it is rather small, in my experience you will be at some point trying to git blame some section of code you don’t understand only to find the finger pointed at your ghost.

The question is one of is it easier to untangle llm code or human?