Firefox introduced Lightweight themes a.k.a Personas in version 3.6. This became available in built-in starting 4.0. The good news is that the Firefox for Android now supports lightweight themes (currently available in nightly builds)! This uses the same themes as desktop Firefox from getpersonas.com and optimizes the images based on the resolution of the device.
We wanted to show as much persona as we can, yet retain the affordance provided by the buttons. To achieve it, the gray or black texture of the buttons will have a translucent layer of the image, making the image flow smoothly between interactors. Also, the about:home reflects the background from the image by taking the dominant color from the image. The experience isn’t complete if the tabs menu and the awesomescreen are left behind. We’ve got that covered as well!
There are few more bits getting reading to join these bytes — like the text color in about:home and the url-bar transparency. But still, what are you waiting for? Try out a nightly build and help us improve the Firefox for Android to make it more personal for you!
P.S.: Just in case you wanted to get back to the default theme, hit Menu > Tools > Addons and disable the theme.