The /etc/xdg/user-dirs.defaults file is a text file that contains the default values for the XDG user dirs which are used by the xdg-user-dirs-update command.
This file contains lines of the form
The following names are recognised:
The values are relative pathnames from the home directory and will be translated on a per-path-element basis into the users locale.
Lines beginning with a # character are ignored.
The user-dirs.defaults file is located in this directory. The default is /etc/xdg.