As best i recall, they come out of a misuse of Fragments elements.<p>The original idea of Google&#x27;s Fragments framework was to produce something closer to desktop interfaces on tablets. But interfaces that could also &quot;collapse&quot; to fit the &quot;card stack&quot; thinking of earlier Android.<p>Meaning that what we now know as the hamburger menu was meant to show up as a sidebar in tablet layout, and as a first layer in phone layout.<p>Similarly, Fragments gave us the actionbar where earlier there was a dedicated menu button. The icon was for when the number of bar entries didn&#x27;t fit the available screen space.<p>Again the thinking seemed to be that the bar would revert back to being the menu on phones.