UIWIndow not announced iOS 4.3 AppDelegate

I just downloaded the latest iOS SDK (4.3) and noticed that when I launch a window-based application, UIWindow is not declared in the header file, it is only referred to as a property.

#import <UIKit/UIKit.h>

@interface GleekAppDelegate : NSObject <UIApplicationDelegate> {
    IBOutlet UILabel *label;
}

@property (nonatomic, retain) IBOutlet UIWindow *window;

@end

I would expect and remember from the old SDKs that the above code should be

#import <UIKit/UIKit.h>

@interface GleekAppDelegate : NSObject <UIApplicationDelegate> {
    IBOutlet UILabel *label;

    UIWindow *window;
}

@property (nonatomic, retain) IBOutlet UIWindow *window;

@end

Is this just a new SDK feature?

thank