On Mon, 25 Jan 2016 11:00:17 -0800
Ian Zimmerman <itz@???> wrote:

> How does the switch away from XUL, a UI framework, affect a core HTTP
> browser feature? Other than possibly making it necessary to develop
> new UI for it, which is presumably the case for many other features
> as well.

IIUC, in this discussion "$XUL" expands to XUL/XPCOM/XBL.