[OliverJones]

When I'm coding / debugging with a framework of some kind (nodejs, dotnet, jdk, wordpress, whatever I'm using to deliver value at the time) I sometimes "step into" the framework or a library to see what happens. (Of course, I need open source for the framework/lib for this to work.) It sometimes opens a window to interesting code to read that's relevant to what I'm thinking about at the time. And sometimes doesn't.

Lots of source these days has auto-documentation comments. Good IDEs present that documentation, which helps guess what might be worth diving into the Step Into rabbithole.

Often, from a high-quality framework / library I learn a bunch about handling weird edge cases and about writing code for long-term maintainability. And, I often learn some useful constructs and techniques. (And, it's possible to learn useful things from not-so-high quality code too.)