The DITA Open Toolkit, or DITA-OT for short, is a set of Java-based, open source tools that provide processing for DITA maps and topic content.
DITA Open Toolkit is an open-source publishing engine for XML content authored in the Darwin Information Typing Architecture, providing extensible publishing power for DITA workflows. See http://www.dita-ot.org/.
Your repository can contain multiple DITA-OT versions. When a user executes the Compose with DITA-OT command, the Compose Output dialog allows the user to select which DITA-OT version to use, what output type to compose, and optionally specify custom parameters or composition profiles to use for that job.