Worked on the lukasolson/kibana repository to deliver a comprehensive upgrade of the Elastic UI Library from version 102.3.0 to 103.0.0, focusing on frontend and UI development using TypeScript. The project involved updating key components such as EuiResizableCollapseButton, EuiTitle, and EuiListGroupItem, as well as implementing new color tokens and addressing breaking changes to maintain visual consistency. By aligning the application with the latest Elastic design system, the work improved UI stability and maintainability. The upgrade also included bundled bug fixes, reducing future upgrade friction and enhancing developer velocity through updated theming and component library integration.