No turning back from new Firefox design Australis
Mozilla has been preparing a new look for Firefox, one that takes its cues from both mobile and touch screens, but it will be difficult to reverse course once implemented.

The new Firefox design that's coming in 2014 is almost ready for wider public testing, but word that it's on its way arrived Friday with a warning: Going back won't be easy.
Code-named Australis, the design project aims to unify the browser's look across multiple platforms, from desktops to mobile devices. Visually, it sports some button placement changes, emphasizes icon-based menus, and is touch-friendly.
While add-ons will probably let you return to the current or an even older design, once Australis hits the Firefox Nightly builds, there's no easy way out.
"Due to its large scope, Australis couldn't be implemented with the ability to toggle its presence via an about:config preference," wrote Jared Wein, a senior software engineer at Mozilla. "This unfortunately carries with it a more burdensome plan to undo the changes should there be issues that lead us to delay the release of Australis."
Mozilla plans to track the nonvisual elements in a separate nightly build, in case it chooses to keep Australis in a holding pattern for a release cycle or two.
Mozilla also gave us an early look at menu design tweaks, which include large icons in menus that look big enough to handle touch screens -- almost an Android-ification of the browser.