LibreOffice

LibreOffice(Document Foundation) is a fork of OpenOffice(Sun, then Oracle), which used to be Star Office.

LibreOffice provides most of the commonly used functionality of Microsoft Word, Excel, and Power Point.
 * LibreOffice opens more proprietary formats than OpenOffice, and moves slightly away from Java dependencies.

As document generation is moving to the cloud, This open source project remains important.

ODT file format.

https://wiki.documentfoundation.org/Events/2014/Seattle_LibreFest