That's a pretty lousy pic. What "feature" are you trying to point out? I'm assuming we are looking at the keel, from aft looking forward? Is it the mounting recess you mean? Or the apparent "flat" trailing edge at the top of the aft end of the keel?
Total Wild Ass Guess here. I know nothing official nor do I have any personal knowledge. But maybe they expect as part of commissioning and bottom painting that the owner would/should fill recess with fairing compound?
As far as flat trailing edge, maybe the thinking is that there is some turbulent flow that close to hull anyway, and so to enable greater thickness in the keel area for aft most keelbolt, the flat doesn't really add any notable drag?