That could be used to identify specific holes. The part has ten holes total. Two have countersinks and are not "coded". A third hole of a different size is not coded as well. The remaining holes are coded in groups of two, two, and three based on size perhaps. I'll see if there are any other ideas.
I have a drawing with three holes dimensioned with True Position requirements. Below the standard True Position dimension is the word "CODED" followed by a True Position symbol with two quadrants blacked out. I have three different versions of this callout, each having different quadrants black...
