WindowsMania.pl, who always manage to get their hands early on ROMs, appear to have managed to get their hands on a device running Project Spartan running on a handset.
The pictures show the new browser does indeed have the address bar at the top of the page, but at least the browser does not feature the dreaded hamburger menu.
Of note is that the Hub appears to be a pretty important element of the browser, and would presumably allow one to keep articles for off-line reading. It will also be where favourites and history are stored..
See the screen shots in the gallery below.