What is CIFilter's inputRequestedSushiMode?

If you initialize a CIFilter with RAW photo data, and look at the inputKeys, you will see the inputRequestedSushiMode key.


There is no documentation anywhere for this key. In fact, if you search for it on google, you'll only find my Tweet about it.


If you look at the attribute's value from a RAW file, you'll see an integer assigned to it. What is this for?