Just to be clear, my local build does not seem to pick up Setup and instead uses Setup.stdlin.in, so @asottile could you please confirm that this is good? Thank you.

this looks correct to me -- or at least it matches the other ones. I could run a test build but that's going to take more time than I have free today :(

this looks correct to me -- or at least it matches the other ones. I could run a test build but that's going to take more time than I have free today :(

There is no way to get Modules/Setup "correct"; it never will be and it never has been. It should be removed, and the (few, hopefully) projects depending on it should find other ways to get what they need.