I spend a lot of time browsing GitHub, not only to find tools, but to understand how good software is structured.

This is not a “best repos of all time” list. More like a personal list of repos I keep coming back to because they teach something: architecture, performance, dev tooling, systems design, UI, or just taste.

1. git/git

Git is one of those tools everyone uses and almost nobody fully understands.

The repo is worth studying because it is old, practical, and deeply battle-tested. There is a lot to learn from how a tool can stay relevant for decades without becoming trendy.

2. torvalds/linux

The Linux kernel is probably the most obvious nerd repo, but it still belongs here.

Not because I understand every part of it. I do not. But reading around the repo gives you a feeling for scale, maintainership, hardware boundaries, naming, review culture, and the amount of discipline needed to keep something this large moving.

3.…