Shimmy focused on maintaining and upgrading package dependencies within large-scale Nix-based build systems, contributing to both the GaloisInc/nixpkgs and Shopify/nixpkgs repositories. They upgraded the Coppwr package to version 1.6.1, ensuring reproducible builds by updating Cargo.lock dependencies and package metadata using Nix and Rust. In Shopify/nixpkgs, Shimmy delivered a targeted upgrade of the Pipeline package to v2.5.0, synchronizing source fetcher revisions and hashes while validating CI pipelines for downstream compatibility. Their work emphasized packaging hygiene, dependency management, and build reproducibility, demonstrating a methodical approach to ecosystem maintenance and risk mitigation in Rust and Nix environments.