What is meaning of "sushiFactor" in _rawDictionary of CIRAWFilter object?

If I create a CIRAWFilter object from a Raw image URL, the resulting object contains an NSDictionary titled, "_rawDictionary".

One of the entries in this dictionary is called "sushiFactor". I see this entry for multiple Raw images from various camera manufacturers.

Is this an industry-standard TIFF Tag in the Raw image community?

What is the meaning of its value?

What is meaning of "sushiFactor" in _rawDictionary of CIRAWFilter object?
 
 
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