Remember when it was time to fire all the engineers because your business-analysts could just make UML diagrams?

If the code is the specification, then the only word on what the system is supposed to do is what it actually does.

When what it actually does is surprising, maybe you can make sense of it by asking the author what they were thinking. But that only works if the author is an entity that is both capable of thinking, and of remembering what it was thinking.