Charles Horowitz updated the CMSgov/dpc-app repository to improve development hygiene by refining the project's .gitignore configuration. He excluded all contents within the tmp/ directory from version control, while retaining a .keep file to support local development workflows. This approach, implemented using Git and configuration management best practices, reduces the risk of accidentally committing temporary files that may contain sensitive data, thereby aligning with security and compliance requirements. The change was captured in a traceable commit and addressed a specific issue in the project. The work demonstrated a focused application of Git and configuration management skills to enhance repository security and usability.