Shined up real nice.
Greasy Fork is available in English.
If youtube is in the new 2017 YouTube Material Redesign, automatically restore classic view
This script was created because my youtube scripts (Youtube Play Next Queue and Youtube Search While Watching Video) don't work with the new youtube redesign. But you can certainly also use this for other scripts that only work with the old classic youtube.
If you want to use material youtube again: