YouTube Popout Player od Ryan Thaut

Overview
This browser extension provides a simple way to open any YouTube video or playlist (including videos and playlists embedded in other sites/pages) in a configurable "popout" window which you can freely position and resize.

Usage
While viewing any YouTube video, whether directly YouTube, or embedded on any other website, you can use any of the following methods to open the popout player for the current video/playlist:

• Right-click on the video and click the "Popout Player" option (at the bottom of the menu that is displayed)
• Click the popout player icon (a square with a smaller square coming out of the top right corner), which can be found in the lower right corner of the video (by the settings and fullscreen icons)
• Use the keyboard shortcut (default Ctrl + Up Arrow )