Greasy Fork is available in English.
Hover a thumbnail on youtube.com and click an icon at the right: "Not interested" and "Don't recommend channel"
< Spätná väzba na YT: not interested in one click
Still works for me. I guess Youtube is updating the site and you're seeing it but I still see the old one.
Thank you for replying. I tried reinstalling the script and restarting Chrome but the problem persists. I'll let you know in case it somehow returns to normal.
I think Youtube broke this script. The buttons don't appear anymore on the video thumbnails; they still appear when the thumbnail enlarges and starts playing, but they have no effect.