This looks like a wonderful new tool from Logos Bible Software:
From the website:
Noet is a suite of tools and texts for scholarly work in the classics. The mobile and web apps launch this fall; next comes an even more robust desktop version. Noet serves disciplines that involve original-language research and text comparison—classical studies, philosophy, intellectual history, and more.
The mobile research app will give professors, students, and scholars advanced scholarly resources: original-language tools, fast searches, and side-by-side study of related texts. The desktop version will introduce even more advanced features for original-language research, as well as a social platform for students and researchers to engage the classics together.
See also: Michael Heiser, “Introducing Noet: Scholarly E-books for Classical Literature and Philosophy”