Check whether it's worth watching a video before actually clicking on it by peeking it's visual or verbal content, description, comments, viewing the thumbnail in full-size and displaying the full title. Works on both YouTube's desktop and mobile layouts, and is also compatible with dark theme.
< Feedback on YouTube Clickbait-Buster
Still works on Firefox but only on home / and channel {@whatever} / and search results pages -- see https://greasyfork.org/scripts/439305-youtube-clickbait-buster/discussions/295035
But that may not last long with more YT layout changes sure to come.
I recommend that you use the extension instead. It's much more up to date than the userscript. I don't intend updating the userscript anymore. Here you can find the extension store links.
No longer works due to YouTube's new layout