The daffodil/daffodil-extra directory is an empty module intended to contain links to other git/svn repos where there are other projects that fit into the regular daffodil sub-module structure, but which for whatever reason, aren't part of its source tree.

There are several DFDL schemas now maintained at github: https://github.com/DFDLSchemas.

Each has its own git repository.

You clone that repository e.g., for NACHA (which runs on Daffodil) take these steps:

Then these sorts of things will work:

Each of these repositories has an eclipse project in it that you can import.

The symlinks to be setup are these (vCard, NACHA, and HL7 are a little different from just pointing at the repo root)