The GNOME Configuration Editor is an important tool.
But at the same time it's a danger one if not properly used.
It resembles the Windows Registry HKEY_CURRENT_USER.
To make sure that GNOME Configuration Editor is installed:
$ pkg info -r gconf-editor
Name: gnome/config/gconf/gconf-editor
Summary: GNOME configuration database editor
Category: Applications/Configuration and Preferences
State: Installed
Publisher: solaris
Version: 2.30.0
Build Release: 5.11
Branch: 0.175.1.0.0.18.0
Packaging Date: June 11, 2012 10:24:12 PM
Size: 1.52 MB
FMRI: pkg://solaris/gnome/config/gconf/gconf-editor@...
It won't appear anywhere on the GNOME desktop.
Naturally it can be started from the shell as most applications.
But I prefer to use the GNOME Run Application invoked by Alt + F2.