[happytoexplain]

This icon is gaining traction fast. I've seen it a lot over the past few years. "Tuning" and "adjusting" is a slightly more specific concept than "settings". I think users associate the "settings" gear with whole-app settings, or "technical"/"system" settings, and it might be something they're loathe to click on because that's typically a large forest of things they don't care about or understand.

Also, I think using not-well-known icons is actually underrated (see my comment here: https://news.ycombinator.com/item?id=35793362)