Activate the New Transparent YouTube Player With This Cookie
Google is currently experimenting with a new transparent player. If you would like to activate it for yourself, you can do so with a simple cookie edit.
The new transparent player is mostly an aesthetic update to YouTube (although it’s more than welcome after years with the same player), however it has one feature that most other players have had for some time: it disappears while you watch a video and appears again only when you hover over the window. If you want to give it a try, you just need to edit one cookie. Chrome users will need an extension like EditThisCookie to change it. Install the extension, open YouTube and click the extension’s icon. Then find the following cookie:
VISITOR_INFO1_LIVE
Then change its value to the following:
Q06SngRDTGA
Firefox users can do the same without an extension using the developer console. Just press Shift-F2 while on YouTube and follow this guide to edit cookies.
How To Activate The Transparent Design Of Your YouTube Player | Gaki