GConf — GNOME under the hood
Gconf is a system built in GNOME 2 which stores applications’ preferable configuration data as well as graphical environment variables in its own files.
The direct predecessor of the Gconf was Gnome-config. It was a very simple configuration system based on INI files. Such solution has lived up to its promises in case of small applications. Therefore Gconf was implemented in GNOME 1.4 already, but only in GNOME 2 it started to be used on a larger scale. Gconf’s inner structure resembles that of Windows Registry, albeit the similarity is rather little. Only the graphical interfaces of their key managers evince resemblance.
All data is kept in XML files distributed within appropriate directories. First, the file /etc/gconf/gconf.xml.mandatory is read only for non root users by default.