This is known as "DavidT Carry" over at CPF. It's an alternate carry rig for a headlamp, specifically a Zebralight. It weighs 0.2 oz for the band, which is a flat boot lace, a Walgreen's elasticized Finger Sleeve, and a cordlock. With the (vintage) H50 light and no battery, this rig weighs 1.0 oz. Add a lithium AA and you're up to 1.6 oz total.
Dual usage, of course, on the lace, sleeve, and cordlock, if needed. (Lace can come in darned handy for a bow saw.)
If you wanted to get even more minimalist, you might be able to replace the finger sleeve with two o-rings, but I haven't tried it.
It can be used around the forehead like a traditional headlamp, but it's also very useful worn loosely around the neck, which is how I often carry this. And unlike the stock head band, you can easily wind it up and stick it in a pocket.
PS: Not sure Walgreen's carries the elasticized finger sleeves anymore. But Amazon does.
PPS: Those of you who are Zebra enthusiasts will certainly have a good joke at my old H50, Zebralight's first headlamp. The reason I keep it around is, I like the old style lock-out twisty switch, which is great for travel. You can't turn it on accidentally. I once turned on a H501 in my pocket by mistake and it got too hot to touch. The H502 has a recessed switch and is very unlikely to accidentally switch on, but the old H50 is foolproof. Sadly, the H50 beam is pre-w and pre-c, so it has that flat tint--which is OK for reading in a taxi cab, the main job of this travel setup. For backpacking, I switch out for an H501w or an H502c.