Yassine Haouzan focused on stabilizing dependencies and improving UI reliability across two open-source projects. In quarkusio/quarkus, he addressed build and runtime conflicts by explicitly setting the jboss-logging-annotations dependency to the 'provided' scope, enhancing CI reliability and cross-environment consistency using Java and build tools. Later, in lichess-org/lila, he improved front end stability by implementing CSS overflow handling for mini-board and mini-game components, ensuring content remained within boundaries and enhancing layout consistency on various devices. His work demonstrated careful attention to dependency management and responsive design, with clear, traceable commits that support ongoing maintenance and review.