Location of launchers, panels, etc. in Gnome

The files that specify the different folders and buttons of the Gnome user interface are somehow really badly distributed all over the place. Here are just a few of the more common locations:

Icons in the panel: ~/.gnome2/panel2.d/default/launchers/
Contents of Start Here: ~/.gnome2/vfolders/start-here/
user's Home, Trash and Start Here: ~/.gnome-desktop/