Jeongseok Jeong worked on stabilizing the build process for the wemixplay/wemixplay-ui repository by updating project dependencies and build scripts. Focusing on dependency management, Jeongseok revised the package.json file to ensure compatibility with current library versions, which reduced build risks and improved long-term maintainability. The work involved careful analysis of existing dependencies and scripts, followed by targeted updates using JSON to define and manage the new configurations. Although the scope was limited to a single feature over one month, the changes provided a more robust foundation for future development and streamlined the build process for the WemixPlay UI project.