I realize this is a personal project, but this is deeply amusing considering that:

1. Way back when (circa 1998-2001?), the Mozilla project started as a radical redesign of the next gen Netscape browser. One of the core principles of the architecture was that the browser itself would render the UI elements (using an HTML-like tech call XUL).

2. The Firefox browser (then called "Phoenix") was a reaction against the above, which was thought to make the browser too heavyweight and slow. Originally Phoenix was the Gecko engine in a native UI window without all the XUL overhead (and without all the other components of the Mozilla Suite like the email client).

Now we're seeing the reverse trend, 15 odd years later.

EDIT: It turns out I misremembered about Phoenix dropping XUL completely--rather they dropped XPFE for a "new light-weight XUL toolkit", along with dropping all the non-browser components of the Mozilla suite.