We use the Concurrent Versioning System (CVS) to cooperatively work on the source code. Basically this means that there is a common source tree on an Internet server (in this case, the one of Netlabs) which allows multiple people to work on the sources at the same time. CVS is then responsible for keeping all the changes in sync.
If you are interested in getting the &xwp; source codes, you can do one of three things:
This is probably a good point to start since you don't have to understand how CVS is working.
cvs.txt
which explains in detail what you need to do.