During February 2025, work focused on developing immutable FMultiMap and FSet data structures for the fungover/breeze repository. These Java-based collections were designed to provide safer, side-effect-free state management and facilitate reliable multi-value mappings. The implementation emphasized concurrency safety and easier reasoning about data flows, leveraging principles of test-driven development and robust unit testing. Comprehensive tests were written to cover add, remove, and retrieve operations, including edge cases such as null values and empty collections. No bug fixes were required, as the primary goal was to establish a solid, maintainable foundation for future enhancements using data structures and immutable collections.