prepareForSegue and PerformSegueWithIdentifier sender

Question

I am wondering about how the functions in the title work and also about the sender parameter.

Lets say a button click calls the performSegue method, does that also call

Answer 1

Updated Method for Swift 5

performSegue(withIdentifier: "showNextViewController", sender: self)

Note : "showNextViewController" is identifier added for segue in storyboard