Worked on enhancing the Esri/abseil-cpp repository by clarifying the documentation and improving test coverage for the flat_hash_set container. Focused on specifying that keys must be MoveConstructible rather than CopyConstructible, the work included updating usage guidance to better align with the actual API requirements. Developed a MoveOnlyInt-based unit test in C++ to verify that non-copyable but movable keys are supported, ensuring correctness and reducing potential misuse. Emphasized software documentation and unit testing to streamline onboarding for new contributors and users. The changes aimed to make the API expectations clearer and the codebase more robust for future development.