One common request we get in Fennec is the ability to show url’s in the titlebar. At one point I even wrote an addon to do it. Ignoring the arguments for and against, the feature is finally available built in to Nightly builds:
To enable, just open Settings -> Privacy and change the “Title Bar” pref to “Show page address”. We’ve also set up domain highlighting like you see on desktop Firefox (for both regular and private tabs show above, with or without Personas enabled, although Personas are a nice security measure for our new scroll away urlbar too!). Enjoy!