Contributed to the ocaml/dune repository by developing the 'dune promotion show' command line subcommand, which allows users to preview the contents of corrected files before applying promotions. This feature was implemented in OCaml and focused on enhancing workflow safety and efficiency by reducing the risk of incorrect file promotions. The work involved designing a user-centric command line interface, handling file operations, and writing automated tests to ensure reliable behavior. Emphasizing test-driven development and code quality, the contribution improved the overall user experience and product reliability, demonstrating skills in CLI development, file handling, and collaborative open source engineering practices.