Perhaps your answer is here
http://www.zdnet.com/article/mozilla-moves-australis-themed-firefox-29-to-beta/where it's talking about Firefox 29 and says
Australis is Mozilla's effort to bring a cleaner look to the browser and includes a new "customisation mode" in the pop-out settings menu, which hosts standard tools and provides a space for third-party add-ons to be installed.
Computerworld also says Firefox 29 with its "Australis" UI sent people looking for other browsers.
http://www.computerworld.com/article/248...ternatives.htmlSo maybe you're looking for Firefox 28.
However what I do is use a recent Firefox with the "Classic Theme Restorer" and "Downloads Window" add-ons and make it look like an old version.