http://maidzonekwrk4xbbmynqnprq2lu7picruncfscfwmyzbmec6naurhyqd.onion/blog/2025-06-03-ios-web-haptics.html
The implementation: github.com/imputnet/cobalt/blob/main/web/src/lib/haptics.ts TLDR: They just create an <input type="checkbox" switch /> element, wrap it in a label, and click it, then it gets removed from the DOM. Easy stuff, really.