Dconf is the hidden configuration settings used in the GNOME desktop environment (within elementary OS). Please also tag with the related application.

Dconf and dconf-editor manages configuration settings within the GNOME desktop environment, which is used in elementary OS. It can be used to customize defaults in applications or to enable tweaks that were once deactivated by design.

from Wikipedia Commons: https://commons.wikimedia.org/wiki/File:Dconf_Editor_0.20.0.png