Worked on stabilizing the Buck build process by restoring lazy import functionality in the facebook/buck2 and facebook/buck2-prelude repositories. Addressed build failures and broken behavior caused by the removal of FbsourceRoot and BuckMode code, reverting previous changes to reintroduce these components. Utilized Python and Python scripting to coordinate a cross-repository rollback, ensuring that downstream targets experienced more reliable builds and smoother development cycles. Focused on software maintenance and build system development, the work improved build stability and reduced the risk of future breakages due to code removals, demonstrating a methodical approach to maintaining complex build infrastructure.