During December 2024, pdr focused on build system hygiene for the denoland/chromium_build repository by removing the unused jitter tracking header from the build whitelist. This targeted code cleanup in C++ reduced dead code and simplified the build graph, directly supporting faster build times and easier long-term maintenance. By identifying and eliminating obsolete references, pdr improved the maintainability of the project and set a foundation for more efficient development cycles. The work demonstrated strong skills in build system management and C/C++ project maintenance, with clear commit documentation ensuring traceability. No major bugs were reported or fixed during this period of focused improvement.