The thing is, reading code is hard. Even well written code is hard to read and grok, the other kind can take days to absorb.

But it is very effective as a way of spotting certain kinds of bugs, while at the same time gaining a much deeper understanding of a codebase.

Reading code in a non trivial way is a very special skill that not many developers have, but that is very worthwhile to attain.

Whenever I come to a new codebase, I start by grabbing a pretty random bug and reading the code in that area. just flicking through, forcing myself to ask questions about it and finding out the answers.

actively engaging with code like that is an amazingly effective way of absorbing a codebase.