What are examples of code that ever programmer should have read and analysed because they show a particularly deep insight into the problem, a creative attempt at a solution or otherwise outstanding proficiency?
Goal is to learn something from excellent pieces of code, much like it is practised in art by studying Old Masters, pieces of literature or musical compositions.
PS: I admit to exaggeration in the headline / first paragraph ("should have") btw ;)
Every programmer should read the (presumably open source) code they depend on, but almost nobody does it. Some look at documentation, but not everyone even does that. What you may find is that some of the code you depend on is garbage, and may even motivate improvements.
This may be less feasible for giant messes such as most front-end tooling and frameworks that exist today.