Thanks for the feedback!
I agree that the examples should use best practices; I already made a lot of changes like List → list. I noticed in the section you linked (about type aliases) that I missed some Type[T] instances, so those still need to be fixed.
I don’t know if it’s worth to avoid using concepts in examples that have not yet been used. It seems difficult to do in all cases, and the audience for the spec should have a general familiarity with typing concepts already. The user-facing documentation is a separate project and need not follow the same structure.
Yes, feel free to report these. Note that the spec will be moved to a different repo (python/typing) eventually, so any CI setup would also need to be transferred later.
PEPs are meant to be historical documents that shouldn’t change after they’re implemented. This process is meant to reduce the reliance on old PEPs in the typing community. The PEPs we incorporate should get a banner pointing to the typing spec as the up-to-date canonical documentation.
I feel the logical choice is to make each of the top-level sections its own page. However, “Type system features” might need further splitting.