Alfi Maulana focused on improving build reproducibility and dependency management for the rerun-io/rerun repository. He reworked the CMake build system to fetch the Apache Arrow C++ dependency via a deterministic tarball download, replacing the previous Git-based approach. By integrating MD5 checksum validation and disabling download progress reporting, Alfi ensured that builds are both stable and produce concise, readable logs. His work in build system configuration using CMake addressed issues of build variance and simplified continuous integration workflows. Over the course of the month, Alfi’s targeted changes enhanced maintainability and made diagnosing build issues more straightforward for the development team.