[rudasn]

If you want to write you first need to read.

You can go through the django source code, documentation, pull requests, mailing lists, tickets, and find all you need to produce serious software.

WireGuard too, but that's in C and in Go. It's a lot of fun seeing how the guys from tailscale submit patches to the wireguard-go library, and how brutal (in the best possible way) Jason's comments are.

[sargstuff]

Note: Things noted to go through and read also are typically what's done both before/after and while code is supported as part of the process of producing production-grade code. aka testing is based on coding design specifications.

documentation (user, designer, programmer/coder, etc) outlines what can expect of code for a given code release without actually having use/look at the code.

open bsd is one example[0]

[1] : https://www.openbsdhandbook.com/