DITA
From Just Solve the File Format Problem
DITA (Darwin Information Typing Architecture) is a format for topic-based authoring and publishing developed by OASIS (Organization for the Advancement of Structured Information Standards). It is an XML-based format.
DITA files normally have the .dita extension, but sometimes use .xml. Other things used in the DITA standard are map files with a .ditamap extension and conditional processing profiles with a .ditaval extension.