Worked on the fmtlib/fmt repository to address a critical compatibility issue with C++20 modules. Delivered a targeted bug fix by implementing conditional inclusion of the <locale> header, ensuring that builds with FMT_MODULE enabled would not fail due to unnecessary dependencies. This approach preserved full C++20 standards compliance while supporting module-based builds, reducing maintenance friction for developers using modern toolchains. The work demonstrated expertise in C++ development, build system optimization, and module management, focusing on stability and forward compatibility. No new features were added during this period, but the fix improved the reliability of the library’s build process.