During November 2024, Lionel Untereiner enhanced the GEOS-DEV/GEOS repository by developing advanced data I/O and external data integration features for simulation workflows. He implemented a configurable aggregation mechanism for VTU output files, allowing users to control output granularity. Leveraging C++ and CMake, Lionel introduced modular components for managing and loading mesh data from external VTK sources, including the ExternalDataSourceManager and ExternalDataRepository. This work established a scalable foundation for flexible data management and reproducible simulations, supporting large-scale parallel computing. The depth of the implementation addressed both extensibility and interoperability, though no major bugs were reported during this development period.