Worked on enhancing the stability and portability of the leanprover/lean4 codebase, focusing on resolving a compatibility issue between C++ environments and GLIBC. Addressed a specific bug by updating the free_sized declaration to include the appropriate noexcept and nothrow attributes, ensuring compliance with GLIBC requirements and preventing build failures during compilation. This targeted fix reduced CI noise and improved cross-environment reliability for Linux builds. The work demonstrated a strong understanding of build systems, C++, and compiler toolchains, emphasizing performance-conscious engineering and careful attention to platform-specific details without introducing new features during the development period.