System/Library/PrivateFrameworks/MapsUI.framework

_MUVariableBlurView.h

NSObject
>
UIResponder
>
UIView

@interface _MUVariableBlurView : UIView

+ (Class)layerClass;

- (id)backdropLayer;
- (id)initWithRadius:(double)a0 maskImage:(struct CGImage { } *)a1;

@end