My Bell Super Air mountain bike helmet (removable face guard) came with an undocumented snap-in GoPro mount. I figured I'd use it to hold a NiteRider light for night trail rides (a relatively common Minnesota activity, we use one bar light and helmet light). This was more of a journey than I expected, so I wrote this up to share.
The first mistake I made was treating the Super Air GoPro mount as removable. It broke and in COVID times it took months to get a replacement. When you snap that thing in don't try to remove it; I think it's designed to safely break under stress.
You can see the mount on the photo below, as well as my light, the NiteRider approved K-Edge adapter ($30 with shipping!, but if you know what to look for you can get it via Amazon for $20 with Prime), the remnant of a Best Tek Amazon adapter (very good except it broke after 3 uses, $10) and "Suptig thumbscrews for GoPro" ($7).