A KefinTweaks walkthrough describes adding watchlists, series-progress views and subtitle controls to Jellyfin’s web interface. Setup uses JavaScript Injector and File Transformations, followed by a server restart and client refresh. It targets Jellyfin Web and official mobile apps built on that interface, not native Android TV or clients such as Findroid and Moonfin. Some preferences are client-specific, so every screen in the home will not automatically share the same configuration. Check the apps actually in use before installing.