Android caught up with other operating systems in terms of aesthetic elements since Matias Duarte took charge in 2010, his first work at Google was the creation of the User Experience interface for the version of Android that was intended for tablets called Honeycomb and carried the number 3.0. This new interface didn't help to sell Android tablets that much, but it certainly had some elements that made it look more refined than any of the previous versions of the OS that were used in smartphones and some elements made it look kind of futuristic. Some months later, Android 4.0 called Ice Cream Sandwich came along with a clear influence from the design language used in Honeycomb and with it, Google introduced a font that would be used across the entire OS: Roboto.
Featuring geometric forms and subtle curves, it was created specifically for the UI with support for high-resolution screens and easier readability in mind. Since then, the font created by the designer Christian Robertson has not only been used in Android, which received a redesign that has been an integral part of the new Material Design language introduced in Android 5.0 Lollipop, it is also used in Chome OS as well as in most of the services integrating Google's ecosystem like Google Play or Google Maps. Since its creation, the font has been available under the Apache license but today it is made open source so that anyone interested can modify it.
The 18 different kinds of styles of the font can be found on GitHub and it even includes one of the tools that was used in its creation. Over the years, the font has expanded its character support and as of now it features the Latin, Cyrillic and Greek characters from Unicode 7.0 and the currency symbol for the Georgian lari that will be published in Unicode 8.0. The number of glyphs included has tripled over time going from 13,000 to 40,000. The idea behind the Android OS has always been to be able to improve the areas that developers consider that could be better so the same thing can now be applied to this key component.