Worked on enhancing the yt-dlp/yt-dlp project by delivering a feature that improved the user experience for selecting video download formats, particularly when downloading multiple formats to stdout. Focused on backend development using Python, the work addressed concurrency issues to ensure correct file paths and robust handling of non-FFmpegFD file descriptors. The implementation refined the command line interface, making interactive format selection more intuitive and reducing user confusion. By strengthening reliability and streamlining the download process, these changes contributed to smoother multi-format downloads and lowered support overhead, demonstrating a thoughtful approach to CLI development and backend engineering within the repository.