Big idea - mini fender

I saw this on the web site of former frame builder, Dave Moulton:
What is that little black tab on the underside of the touring fork crown? I think it's a mini fender meant to keep road gunk out of your headset. These days, you could make it out of a tab of carbon fiber and still be cool. Maybe. Anyway, something to think about.

Photo from http://davesbikeblog.squarespace.com/gallery/