When Mozilla killed Prism another developed forked it off and renamed the project WebRunner, but then it also died a few months later. I’d show you the link but they all report 404 when you visit the developer’s website.
Chrome doesn’t have Application Shortcuts anymore either, and they’re the ones who came up with the concept to start.
For now there is the the Standalone (which is buggy as hell) Firefox extension but it’s buggy as hell and it only really seems to work well on OSX. I tried using it on Windows 10 and it was basically useless.
All of this except for Standalone went down before 2011. It’s 2015 and the only options available that work well are for OSX, and commercial at that. There’s hope that WebRT will revive the concept since whatever lives on the web now has to compete with native apps for each mobile platform. They are their own form of single-site browser, but it all depends on the developer and obviously they’re tracking your every interaction with it. We need something that’s open and everyone can use to create the browsers they need.