I've been writing about how learning and the focus of learning changes in code reviews over time for the code author.

Depending on the experience level of a dev, and their time in a team, they learn (proportionally) different things during code reviews.

For example, a junior dev may receive many comments about their coding abilities and style, best practices, API usage, and team conventions. Fewer of the comments are concerned with architecture or product decisions.

For an experienced dev, few comments are about the code they write.

The discussion & focus of the code review is on the product, maintainability of the code, performance of the solution, architecture.
They also learn valuable insights into team dynamics and project progress.