its this year's water bottle mount
A crown mounted fender would look ridiculous and weigh too much for a weight weenie fork. Basically you'd need an MX fender which is ginormous! At least with DVO's DH fork you can put the crown to arch flap on it.
And yes boom, waterbottle bosses are important. Always have been (and not the bottom of the downtube version which are a recipe for downtube damage).