Worked on the xupefei/delta repository to enhance the checkpointing workflow by refactoring the internal API. Focused on backend development using Scala, the work involved updating the checkpoint function to accept a CatalogTable object instead of a TableIdentifier, thereby enabling the process to access richer table metadata. This change was designed to stabilize and future-proof checkpointing, making it easier to evolve with catalog-based features while maintaining internal consistency. The refactor did not introduce user-facing changes but improved the maintainability and extensibility of the codebase. Emphasized clean refactoring practices and thoughtful API design to support future backend enhancements.