I would suspect the entire depth of the front tread is 6/32 which is pretty standard for front moto tires. That means 4/32 to the wear bars.
My Bridgestone, Avons, and my wife's Michelin's are all 6/32 total tread depth when new.
I bought this bike and it had a metzler front tire that has 4/32 total depth left and 7,000 miles on it. Ought to be good for another 4-5,000, but with no experience with metzlers I will keep a close eye on it.
I can find the total tread depth for Bridgestones and Dunlops but not Metzlers.