The new Kolab 3.1 documentation is written in reStructuredText, using a tool called Sqhinx which was originally created for the Python documentation.
It is much easier to edit than the Publican notation used before for the Kolab 3.0 documentation.
The website for Sqhinx is here: http://sphinx-doc.org/
Some useful links for getting started with writing documentation with Sqhinx:
You find the sources of the Kolab Documentation here: https://github.com/kolab-groupware/kolab-docs
You can fork that repository, make your own changes, even online at github.
For more complex jobs, I recommend cloning your github fork locally, and work there, and commit and push when you are happy.
See also a good tutorial at Github for this: https://help.github.com/articles/fork-a-repo
It also makes sense to build the documentation locally, and have a look at your changes.
On CentOS, you need to do this:
yum install python-setuptools make easy_install -U Sphinx wget http://www.graphviz.org/graphviz-rhel.repo -O /etc/yum.repos.d/graphviz-rhel.repo yum install graphviz-python graphviz-gd git clone https://<your github username>@github.com/<your github username>/kolab-docs.git cd kolab-docs make html
You will find the result in the directory build/html