New ask Hacker News story: Ask HN: How do you discover features in unknown code bases?

Ask HN: How do you discover features in unknown code bases?
4 by hvasilev | 1 comments on Hacker News.
I'm realizing that one of the reasons why I don't do a lot of additional hobby programming is because I'm missing a fundamental skillset that I never developed (in a reliable way) over the years. I think I don't know how to discover features that I'm interested in, in code bases that I'm unfamiliar with. Example: In Chromium I want to find the algorithm that is building the DOM. I'm not sure if that is even part of the code base (https://ift.tt/lUhDn0N) How would you personally approach this problem?