If you are interested in contributing to Eclipse QVTo, we recommend you to use the Oomph setup file, which will prepare the IDE and the workspace with all requried sources.
If you have Oomph installed you simply have to import the QVTo (and optionally OCL and EMF) development setup from the Eclipse.org catalog:
You can also install a new/clean Oomph-ready IDE using the Oomph installer
A very short start guide to Oomph can be found here
You can also information about the source code git repository location and team project set files below