ndla.no consists of two different solutions, both built using  Drupal. The site consists of the Drupal core and a set of modules and themes, some downloaded from drupal.org and some custom made for the project. To stich this together into a working web site, we have created the sites directory, containing the two different sites. The trunk itself does not contain any files, but there is a property called svn:externals attached to it (details about this can be found in the online book  Version Control with Subversion). What it does is pulling all the bits and pieces together from around the repository to create a more or less complete site.