Ask HN: Good Django codebases to read

I've been involved in a migration of a medium-size codebase to Django and it's been a pleasure so far. The code is a lot shorter and easier to contribute to. However, it's difficult to find codebases that solve more advanced problems beyond those discussed in the official Django documentation.

Are there any good examples of mature Django apps that include proper authentication and session handling, caching, a modern API (e.g. using DRF), and other features of the Django framework?