An Overview

From the Apple documentation:

A UIStoryboardSegue object is responsible for performing the visual transition between two view controllers. In addition, segue objects are used to prepare for the transition from one view controller to another. Segue objects contain information about the view controllers involved in a transition. When a segue is triggered, but before the visual transition occurs, the storyboard runtime calls the current view controller’s prepareForSegue:sender: method so that it can pass any needed data to the view controller that is about to be displayed.

Attributes

Swift

sourceViewController: UIViewController {get}
destinationViewController: UIViewController {get}
identifier: String? {get}

References:

• UIViewController Class Reference
• UIStoryBoardSegue Class Reference