Greasy Fork is available in English.
Makes YouTube videos run in high definition + YouTube fixes
< Обсуждения YouTube HD Override
As far as I know, GM scripts don't run inside iframes that satisfy the @include options, which means enabling the script for every page and then detecting YouTube or embedded players. I can't say I like that option.
Do other scripts like YouTube Center work on embedded videos?
Embedded videos
Nice script, but I miss the support for embedded videos. Any chance of adding this functionality?