Franciszek Piechocki enhanced the FAISS repository by expanding its C API to support external language bindings for the PCAMatrix balanced_bins parameter. He designed and implemented getter and setter functions, along with corresponding header declarations and source definitions, to provide full read and write access for this parameter. Focusing on C API development and library integration, Franciszek prioritized interoperability and binding readiness, enabling smoother integration with other languages and reducing future development effort for external bindings. His work demonstrated a solid understanding of C++ and API surface design, delivering a targeted feature that improved the extensibility and ecosystem reach of FAISS.