https://github.com/rust-lang/rust/blob/71a567fae4c282aa5ecb1e6e48f020ade8df23e7/src/librustdoc/html/render/mod.rs
rust/src/librustdoc/formats/item_type.rs
https://github.com/rust-lang/rust/blob/71a567fae4c282aa5ecb1e6e48f020ade8df23e7/src/librustdoc/html/render/cache.rs#L219