Question about a new SplitView Application

When you create a new Split-View Application in XCode, I am trying to get a handle on something.

I am completely not understanding a bit in the DetailViewController.h/.m.

Of course in the .h file, it has the expected:

@interface DetailViewController : UIViewController ......


But in the .m file it also has:

@interface DetailViewController ()

and then another method and property declaration. I have never seen code like this in the .m file.

I can't get my brain around it...

 

Ahh, that makes total sense! I suppose something like this would be required since objective C seems to lack the ability to make private methods (in the traditional sense)

Thanks!