You might be wondering how the storyboard gets loaded in the first place. Just like with MainMenu.xib, the answer is in the Info.plist.
If you check the Info.plist for this project you will
see that the key
NSMainStoryboardFile is set to
Scenes can also be loaded from storyboards programmatically. The NSStoryboard class provides this, much like NSBundle does for NIB-loading. Within a storyboard, one scene can be designated as the initial controller. This is used in the application’s Main.storyboard to designate the application window to be opened at launch.
Controllers within a storyboard can also be instantiated by their identifier, which is set in the identity inspector. ...