It's Android's first OpenOffice Document Reader! 
This is an Android frontend for the excellent ODF Java library called odf2html (formerly JOpenDocument), made by Andi (https://github.com/andiwand/odf2html). Feel free to use it in your own project too, but please don't forget to tell us about it!
More information at http://reader.tomtasche.at/ and in the app itself.