Common on European utility bikes, front wheel stabilizers make loading front racks simpler.
They are a spring connecting the fork to the down tube. They add a subtle self centering action to the front wheel, making loading and unloading of a bike with a basket, or say....our Porteur rack....much easier. You don't fight the bike while putting stuff in it. The front of the bike stays put. The spring offers some resistance to steering, so it counteracts deflections from hitting potholes and road debris, too.
It's pretty universal - any bike with a down tube of 1-1/4" (31.8mm) or smaller can be fitted. It connects to the fork via the brake pivot hole. The hole diameter is made for nutted calipers or a M6 bolt. For recessed mount calipers, minor modification with a drill or a file is necessary. You can also use Sheldon's Fender Nuts to allow the wheel stabilzer to be attached to recessed fitting if you don't want to drill or file it.
The wheel stabilizer is rust resistant, includes all the required brackets and hardware, and has a pinch guard to cover the torsion spring. The little knob adjusts the spring tension.