SmartTube is a free, open-source Android TV YouTube client that replaces the official YouTube app with enhanced features like SponsorBlock integration, adjustable playback speed, 8K/HDR support, live chat, and no dependency on Google Services. The architecture is a modular Android application built on a heavily customized fork of ExoPlayer (v2.10.6, Amazon variant) for media playback, and AndroidX Leanback (v1.0.0) for the TV-optimized user interface. The codebase follows a presenter-view pattern with clear separation of concerns, using singleton presenters and view interfaces. Key entry points include SplashActivity, BrowseActivity, PlaybackActivity, and various settings dialogs. Data flows primarily from YouTube's unofficial API (via SABR streaming protocol) through custom ExoPlayer extensions, with additional integrations for SponsorBlock, DeArrow, remote control, and Google Drive backup. External dependencies include ExoPlayer (forked), Leanback (vendored), Glide, RxJava, WorkManager, and a few third-party UI libraries (chatkit, slidableactivity, filepicker).