You can read Chromium 's source today, and people still spend years reverse engineering Chrome. The code isn't the hard part. The hard parts are the process model the code implies, the Google layer on top of it, and the behavior no design doc covers.

This is a map of where that work pays off, and which repos and docs got there first.

The Part You Don't Have to Reverse

Start with what's documented, because most "Chrome internals" posts reverse-engineer things that are written down. The Chromium design docs tell you to begin with multi-process architecture . Most of the other design documents assume you've read it.

The model is simple to state. The browser and renderers talk over Mojo or the legacy IPC system, and each renderer process has exactly one RenderProcess object. Mojo is also how the browser's own services talk to each other. The network service is designed as a Mojo service that doesn't need to know which thread or process it runs on.…