Oboinus is X11 background previewer and setter. In normal working mode, Oboinus provides an interface that helps you to choose a picture to be set as the background. When the --restore option is passed, it sets the background that it has a configuration for and exits immediately (for use in .xinitrc/.xsession or your WM startup files).
Final Config implements the preference dialogue (typically found under Edit->Preferences) as a separate application that can be used by another application (called the client application or client) through DBus. The available preferences and how they are to be presented to the user is described in an XML file (the desc file), which can be stored in a place convenient to the client. The client does not need to bother with the desc file; it just needs to pass along the file location when invoking the FinalConfig service.