The latest Firefox for Android nightly build
now features a number of changes to the UI
with the goals of "...keeping a clear distinction between different types of tabs; making better use of the screen real estate on different form-factors and orientations; and being more compliant with Android’s design language. ... the tabs tray is now divided into sections for each type of tab — regular, private, and remote — so that you always keep things separate and organized. Furthermore, once you select a private tab, the main toolbar becomes dark as a clear sign that you're in a different browsing mode. ... We now use a horizontal scrolling tabs tray whenever it improves our use of the screen space. This is achieved with a TwoWayView ... We've recently landed a new skin for Firefox for Android that is more aligned with Android's Holo design language. Almost all textures and gradients were replaced by flat colors giving a much lighter feel to the browser."