Worked on maintaining stability and compatibility in the facebook/buck2 and facebook/buck2-prelude repositories by reverting the no-SAN constraint migration. Addressed two critical bugs by restoring the previous constraint implementation, ensuring that existing users and downstream dependencies experienced no disruption. Coordinated a cross-repository rollback to preserve consistent constraint behavior, validating build stability and minimizing risk to ongoing development. Utilized Python for backend development, build system management, and configuration tasks, with a strong emphasis on testing and documentation. The approach prioritized product stability, reduced maintenance costs, and provided a clear audit trail for future reference, supporting long-term maintainability of the codebase.