Hi kazinator, thanks for your comment (I'm the post's author). When I originally wrote the post, I actually had a whole section about "reading for questions", which discussed how the best way to read without modifying a program is to read to answer focused questions you have about the codebase. It kind of got lost when I shifted focus to active interaction versus passive exploration, but I agree that reading with questions in mind is far superior to just reading the code to understand it generally.