[allo37]

I've never worked on large open source projects (except maybe as part of my job), but every new company I join inevitably has some large codebase I have to familiarize myself with. In my experience.

- It just takes a long time: I find I'll spend a good 1.5-2 years at a company before I can finally say with confidence I have a decent grasp on the entire codebase;

- I try to focus on making small changes/bugfixes to specific components. Do that enough and you start to see how things fit together;

- Running the code with lots of logging sometimes helps;

- Finding some sort of high-level architecture diagram or documentation works wonders. Usually in the industry there's one dude(ine) who's been there for a while to set you on the right path, not sure about FLOSS...