system.defaults.dock.showAppExposeGestureEnabled

Whether to enable trackpad gestures (three- or four-finger vertical swipe) to show App Exposé. The default is false. This feature interacts with system.defaults.trackpad.TrackpadFourFingerVertSwipeGesture and system.defaults.trackpad.TrackpadThreeFingerVertSwipeGesture to determine which gesture triggers App Exposé.