Project Fugu DevRel here (https://twitter.com/tomayac)! The way to approach this is with progressive enhancement wherever possible. See https://web.dev/svgcode/ for an example where I try to make this concrete. Well noting that if your app depends on hardware APIs like WebHID, this approach obviously won’t work. What you can always do, though, is let other browser vendors know how and why you want them to support Fugu APIs.