With What does Apple Swizzle the IsA-pointer in KVO?

[Philip Mötteli]

Hi,


Apple says, that it uses IsA-swizzling as the underlying technology to  
implement KVO.
What are/is the class(es), which replace the original class of the  
observed object? Is it an NSProxy subclass? Different NSProxy  
subclasses, depending on the observed object? Is it a direct subclass  
of the observed object?


Thanks
Phil