Sometimes, wearing a headlamp on your head can be a challenge, for example during rain or fog or when using a hat. An alternative is to wear the headlamp around your neck. But this can be uncomfortable and wobbly with most original holders.
This simple plate was designed to use the clamping part of the Skilhunt HB3 headlamp mount. Not only is it a great mount by itself, it is also easy to take apart and to design a compatible bracket for your headlamp yourself.
You can find the 3D model here:
https://www.printables.com/model/1483308-skilhunt-hb3-chestplate
(Before anyone gets worried: there's a weak link in the paracord.)
Yes neck lights are a thing: https://www.harborfreight.com/290-lumen-rechargeable-led-neck-light-58043.html
I like the bracket that you made.