Blank, dim, and mirror your screens in a multi-monitor setup
Each screen can have its contents mirrored in a window. This is useful for viewing what's on an output device that's turned off or physically located in another room. Right-click on a screen and click "Mirror" to open the screen mirroring window.
When the screen mirroring window is open, you can right-click for options (including making it full screen or adjusting aspect ratio of the image). You can also toggle the blank/revealed state of the mirrored screen.
You can also mirror an arbitrary region of the desktop by clicking the Mirror Region button in the main window or in the notification area icon. This will allow you to mirror part of a screen, such as the video portion of a vertical monitor or a non-fullscreen player.
This feature has 3 significant limitations to be aware of: