Is this essentially a JavaScript browser in a browser? When I worked at Netscape (1997), some developer developed one. No real use since you had to use a Nescape browser to run it but it was funny anyway...
Firefox is essentially a javascript browser in a browser to begin with, it's just that Firefox .js works on XUL instead of htlm5/css. The Chromeless project is just replacing the XUL chrome frontend with an html5/css frontend. It's kind of a misnomer because by their definition, Firefox already is chromeless, they're just adding a new API.