I meant to open against my own fork to validate what kindof changes would be necessary and if worth

@hauntsaninja It did allow me to find a couple typing issues with libraries used by typeshed (namely pathspec, tomlkit and yaml), and two (maybe three, to validate) issues with pyright itself.
Fixing those would improve typeshed contributors experience by providing more/better type hints. Bu it's outside typeshed itself.

It also made me realize parsing METADATA.toml could be improved by parsing it in a central location, and returning a TypedDict. That way the default values are constant (no need to re-implement everytime), no need to revalidate keys everytime, no need to constantly do .get and type-hints will be provided.
There's also a couple of keys and values that are not validated rn.

So even if in the end checking scripts and testing with pyright is not something that's done, it will have been a fruitful exercice for me.

Yeah, agreed about METADATA.toml. In stub_uploader this is what I went with: https://github.com/typeshed-internal/stub_uploader/blob/main/stub_uploader/metadata.py Might be nice to have something like that in typeshed too