Worked on the mozilla/gecko-dev repository to enhance session restore reliability by addressing a bug that caused duplicate tab groups after automatic restoration. Utilized JavaScript and Python to modify the session management logic, ensuring that automatically restored tab groups were removed from the saved session state, thereby preventing duplication and maintaining a cleaner session environment for users. Expanded the test suite to simulate scenarios such as closing the last window, validating correct session state restoration under various edge cases. Focused on bug fixing, session management, and testing, the work improved user experience by reducing confusion and potential data duplication across browser restarts.