According to the gconf-editor man page
GConf-Editor is a tool used for editing the GConf configuration
database. It might be useful when the proper configuration utility for
some software provides no way of changing some option.
and
This tool allows you to directly edit your configuration database.
This is not the recommended way of setting desktop preferences. Use
this tool at your own risk.
Also look at the answers in Gconf, Dconf, Gsettings and the relationship between them for an overview on gconf, dconf, and gsettings.
To find which files are modified (edited) when you make your changes, you can use the find command.
find ~/ -mmin -5 -type f
will find all files in your home modified in the last five minutes. You can reduce the time find takes by excluding certain folders:
find ~/ ! -path "*mozilla*" ! -path "*cache*" -mmin -5 -type f
Will exclude ~/.mozilla and ~/.cache from being searched.
To give an example, I used gsettings to modify whether FileChooser shows hidden files and folders:
$ gsettings get org.gtk.Settings.FileChooser show-hidden
false
$ gsettings set org.gtk.Settings.FileChooser show-hidden true
$ gsettings get org.gtk.Settings.FileChooser show-hidden
true
$
I then ran find and saw that ~/.config/dconf/user was modified. That file is a binary:
$ file user
user: data
$
In other words, you can't open it and see what's inside as you would open a text file or even a xml file.
I don't have gconf-editor or dconf-editor installed but you can use the same find command to find which file has been modified when you make your modifications and then use file to figure out whether you can see what that file contains (without using a hex editor).