The light came with an alternate mount that screws on to the handlebar but it makes taking the light off more annoying, and obviously removes the ability to freely put the light on different bikes
I was hoping this design was universal but none of the straps I'm seeing online have the screw hole. Well, there is one very similar strap but I'd have to pay 13€ postage on a 5€ item which offends me on a spiritual level
The screw is for attaching the rubber mounting strap to the headlight itself. The light came with two different mounting options, the strap and a long plastic mounting arm with a Garmin mount on top and a separate mount for the headlight below. There's an alternate hard plastic bit you can screw to the bottom of the headlight for that purpose. You then use a thumbscrew to attach the light to the mounting arm
It's just much less versatile than the strap was