Sysadmins can configure things by editing /etc/xdg/user-dirs.conf. At the moment there are only two settings, you can disable the whole thing, and you can specify the charset encoding used for filenames. They can also set or change the default directories and their initial values in /etc/xdg/user-dirs.defaults.
$(XDG_CONFIG_HOME)/user-dirs.dirs specifies the current set of directories for the user. This file is in a shell format, so its easy to access from a shell script. This file can also be modified by users (manually or via applications) to change the directories used. Note: To disable a directory, point it to the homedir. If you delete it it will be recreated on the next login.