Where are code reviews

I've been told that a good way to learn idiomatic Rust style and learn good/advanced techniques is to read reviews of code submitted (and possibly rejected) for major Rust projects, perhaps including even code submitted to the compiler itself. Where can one find such reviews, please?

Most projects are on GitHub, where you can browse their pull requests for code reviews. Some are on GitLab or elsewhere with a similar mechanism. For example, here are pull requests for the compiler itself: