During November 2024, Berk Yavuz focused on backend development and refactoring within the xupefei/delta repository, targeting reliability improvements in checkpoint metadata loading for Spark-based workflows. He refactored the loadMetadataFromFile function by extracting its core parsing logic into a new private method, unsafeLoadMetadataFromFile, and removed unused code to streamline the codebase. This approach improved the separation of concerns between parsing and exception handling, enhancing both maintainability and testability. Working primarily with Scala, Berk demonstrated a methodical approach to reducing code surface area and confusion, delivering a focused feature that addressed reliability without introducing new bugs or regressions.