YouTube Watched Marker by Giray Bal

Mark the YouTube videos you have already watched, or are not interested in, with one click. Marked videos fade out so new ones stand out.

Features:
* A button on every video thumbnail cycles: unmarked, watched, not interested.
* Works on the home page, search, channel pages, the watch page and Shorts.
* Marked videos are dimmed; hover a video to see it normally. The dimming level is adjustable in the popup.
* Keyboard: hover a video and press W (watched) or D (not interested). Press again to undo.
* Optional auto-mark: videos you open, Shorts you open, or videos whose red progress bar passes a percentage you choose.
* Backup and restore your lists as .txt files, handy for moving them to another browser.
* Playlists and mixes are left alone.

Privacy: your lists are stored only in your browser (local extension storage). Nothing is sent anywhere, no account, no tracking.