Worked on improving installation-time permissions handling in the pimcore/admin-ui-classic-bundle repository, focusing on backend development and database management using PHP. Addressed a persistent issue where duplicate entries could be created in the users_permission_definitions table during installation by implementing idempotent logic that checks for existing permissions before inserting new ones. This fix resolved outstanding duplicate permission problems, enhancing data integrity and ensuring consistent access control mappings across environments. The solution was delivered as a well-documented, targeted change tied to a specific commit, strengthening the installation workflow and reducing potential support and remediation costs associated with inconsistent permission states in production systems.