There are no public APIs for it.
There are two related private API methods onUIApplication I can find (using any of them, you must reject the application from the App Store):
_setReachabilitySupported:that would supposedly enable / disable reachability (e.g. Spotlight)_deactivateReachabilitywhich will return the view to its usual place on the screen
I do not see anything that informs your application that the user has performed this gesture.
UIWindow setFrame:. , , Reachability, .