The company created the new typeface in conjunction with Type Together and has been working on the project since 2014. The idea behind the new typeface was to create an enhanced reading experience across devices and to make Google e-books stand out against other eReader competitors. The company tweeted the news yesterday afternoon.
— Google Play (@GooglePlay) May 18, 2015
Here is more about the project from the Type Together blog:
The electronic or digital book represents one of the most important challenge designers and developers face today. The technical limitations of devices regarding rendering of type, together with their variety of physical sizes, are only two of the main obstacles e-books have to tackle. These facts contribute to an unfair yet appropriate comparison with their analog counterpart, where typography plays a leading role. The Play Books project offered an opportunity to approach some of these problems from a new perspective.