Jaejun Ku modernized the build system for the pytorch/pytorch repository, focusing on enabling migration to Buck2. He removed platform-specific arguments from the build configuration, reducing technical debt and simplifying cross-platform support. Using Python and leveraging expertise in build system configuration and dependency management, Jaejun established a foundation for faster, more reliable builds and improved continuous integration workflows. His work addressed long-term stability by streamlining configuration and supporting future scalability. Although the project spanned one month and involved a single feature, the depth of the changes demonstrated a strong understanding of complex build environments and cross-repository collaboration within large codebases.