crates.io Sparse Index
The crates.io sparse index at https://index.crates.io serves the registry config document plus per-crate newline-delimited JSON metadata files over HTTP, replacing the legacy git index clone. Cargo uses the sparse protocol by default since Rust 1.70 (June 2023). Each index entry records a version's dependencies, features, SHA-256 checksum, and yank state.
Documentation
Documentation
https://doc.rust-lang.org/cargo/reference/registry-index.html
Documentation
https://blog.rust-lang.org/2023/03/09/Rust-1.68.0.html