Alfi Maulana focused on improving build reproducibility and dependency management for the rerun-io/rerun repository by reworking how the Arrow C++ library is fetched during builds. Using CMake, Alfi replaced the previous Git-based approach with a deterministic tarball download, incorporating MD5 checksum validation to ensure dependency integrity. This change reduced build variance and simplified continuous integration workflows, resulting in faster and more reliable CI runs. By disabling download progress reporting, Alfi also produced cleaner build logs, making diagnostics easier. The work demonstrated depth in build system configuration and a strong understanding of reproducible builds, with a focus on maintainability.