The `rust-packaging` RPM was used in the early bootstrap days of RHEL 9 before the decision was made to not use the Fedora-style Rust packaging where there was a separate RPM for every Rust crate dependency.

Rust packagers are expected to bundle/vendor their dependencies into the SRPM of their main deliverable.

The rust-toolset package provides similar RPM macros, without the extra dependency management.

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This information came out of a discussion with the Rust team about the ownership of the `rust-packaging` RPM and how to handle ownership of this package in the future.