This is a tool which converts ReVo XML to a much simplified JSON file. Python 2.X required.
$ mkvirtualenv revo_utils -p `which python2.7`
$ pip install -r requirements.txt
$ cd revo-export/
$ python json_export.py
This will write a dictionary.json into revo-export/.
dtd/ -- .dtd files for ReVo's XML structure
xml/ -- the XML files we extract from
revo-export/ -- all the Python code that does the work
ReVo's documentation could perhaps be more thorough, but is very useful nonetheless. You can find it at http://www.reta-vortaro.de/revo/dok/manlibro.html.
This tool has a MIT licence, see COPYING for details.