Pressing Super+P brings up the OSD with several options, including "Switch to laptop screen". I'm using a standard desktop though, and I don't see much reason that the option shouldn't be called "Switch to main screen" or "Switch to primary screen" instead. My use case is to manage the connection to a TV.
*** Bug 459966 has been marked as a duplicate of this bug. ***
*** Bug 493309 has been marked as a duplicate of this bug. ***