Etna is a software developed by Laurent Jouanneau, at Disruptive Innovations (Laurent doesn’t work anymore for this company since February 2009). It is a project created for Rice University in 2004, to edit documents and articles published on the web, using their own schema CNXML.

Now this is a “standalone” project.

If you want to contact the main author of the editor : ljouanneau at gmail dot com.