@jsbarretto `doc(hidden)` is most often used as a way to "hide" internal unstable APIs, mostly for macros.
There are only few uses of doc(hidden) in real-world crates that are still meant to be used. I reviewed a lot of the most downloaded crates for uses of doc(hidden) and only found 1 actual use of doc(hidden) on a stable API. I later found another one.
I suggested a clippy lint for that, which I believe should be warn by default: https://github.com/rust-lang/rust-clippy/issues/11536
@sgued I'd love to see this lint be a thing, I think it's a great idea! Nice to hear that someone's done the legwork of looking through the ecosystem. I still have some reservations because contract-by-documentation is very much opposed to the Rust ethos, but I suspect it's probably satisfactory for now.