#import <Foundation/Foundation.h>
#import <UIKit/UIKit.h>

@class DetailViewController;

@interface DetailViewController : UIViewController
- (IBAction) unwindToMaster:(UIStoryboardSegue *) segue;
@end

@objc(DetailViewController)class DetailViewController: UIViewController, UISplitViewControllerDelegate {

    @IBOutlet var detailDescriptionLabel: UILabel
    var masterPopoverController: UIPopoverController? = nil

    @IBOutlet var itemButton: UIBarButtonItem

    @IBAction func unwindToMaster(segue:UIStoryboardSegue) {
        NSLog("unwind baby")
    }
[...]
}

<barButtonItem key="rightBarButtonItem" title="Item" id="5Nk-ZI-b7r">
                            <connections>
                                <segue destination="aIR-Or-dY2" kind="unwind" unwindAction="unwindToMaster:" id="aWo-Uk-qUQ"/>
                            </connections>
                        </barButtonItem>