Off the top of my head, some accomplishments from along the way:
- Getting `clap` v3 out (stuck in limbo for years) and then v4
- Polish on and continued maintenance of `typos`
- Creation of `trycmd` to test clap's documentation
- Making `winnow`
- Making `toml_edit` production ready
- Getting `cargo add` into Cargo
- Mentored the work on Cargo's workspace inheritance
- 2 rewrites of `toml`
- Creation of `anstyle` and `anstream`, providing an alternative approach to enriching CLIs
- Significant work to `cargo release`
- Keeping the lights on for many crates at https://github.com/rust-cli/
- Cargo script, from experiments to it being approved for stabilization (stabilization is pending)
- Designed and implemented `[lints]` support in Cargo, an idea people had given up on (which I didn't know at the time)
- MSRV-aware dependency resolver for Cargo (originally thought impossible with the current code base)
- Created a vision and roadmap for improving the test experience for Cargo users
- Pulling `snapbox` out of `trycmd` and making it scale to Cargo's needs
- Mentored work on Cargo workspace publishing
- Led exploration in defining plumbing commands for Cargo
- Led exploration in alternative architectures for `cargo fix` to better scale with large workspaces
- Advocated for a cross-project, user-centric perspective on build performance
- Performance optimizations in Cargo
- Spoke at RustNL, GOSIM, Rust in Paris, and RustWeek