Cast YouTube in Browser per Mark Kray

Control YouTube in your browser from your smartphone or tablet. Enables the YouTube for TV interface in your browser, which is normally blocked on desktop. YouTube TV supports casting from a mobile device.

Click on the YouTube TV button in the extension's pop-up menu and follow the instructions.
Or visit https://www.youtube.com/tv.
Optionally toggle full-screen by clicking on the YouTube logo in the top right corner of the page.
Press the ⚙ button at the bottom left of the page.
Select "Link with TV code".

Tutorial video: https://i.imgur.com/CwvpAAO.mp4

If you're using adblock, you might get a black screen when you open a video. This is in place of the ad that would normally play. The video will play normally after that.