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.)
For running or hiking at night, it's really nice to have light not coming from your head. When a light source is next to your eyes, you never see any shadows, which obscures some obstacles. Some people wear lights on a backpack strap or a waist band to get around this.
Kogalla Ra is a big name for that type of light. Also the Flipbelt light is popular.
This mounting plate could easily be used to work the same way those products are.