As described in the manfiest Cargo.toml has a field called homepage and another field called repository. The latter was designated to be contain the link to the public (git) repository of the project, but for some reason some crates use the homepage field to contain the repository. See the list of Crates with homepage and without repository field.
There are currently 3,854 such crates which is 1.77% of the total number of crates.
A small improvement to the Rust ecosystem is to make sure there is a repository field and it lead to the (public) repository of the project.
This PR was sent as part of the live open source contribution events.
See previous issues: #91 and #104