If you enlarge the photo I think you can make out a normal stirrup front brake operating on the wheel Rim. I was wondering it if it was some sort of speedo drive, or may be some sort of device to measure wheel revolutions and/or loading on the as there definitely seems to be some sort of connection with Hutchison tyres. There appears to be a cable running from the box of tricks mounted on the front fork to some sort of instrument or gauge fixed to the handlebars.
Of course this theory might possible be just a lot of hot air, unlike the rear tyre which seems to suffering from a severe lack of the very self same medium.
Just a thought, I cannot see how it could possibly to operate as any sort of brake, may be people have some other ideas.