/usr/share/gnome-panel/ is in gnome-applets-data 3.5.92-0ubuntu3.
This file is owned by root:root, with mode 0o755.
..
/usr/share/gnome-panel/4.0/
/usr/share/gnome-panel/4.0/applets/
/usr/share/gnome-panel/4.0/applets/org.gnome.applets.AccessxStatusApplet.panel-applet
/usr/share/gnome-panel/4.0/applets/org.gnome.applets.CPUFreqApplet.panel-applet
/usr/share/gnome-panel/4.0/applets/org.gnome.applets.CharpickerApplet.panel-applet
/usr/share/gnome-panel/4.0/applets/org.gnome.applets.DriveMountApplet.panel-applet
/usr/share/gnome-panel/4.0/applets/org.gnome.applets.GeyesApplet.panel-applet
/usr/share/gnome-panel/4.0/applets/org.gnome.applets.InvestApplet.panel-applet
/usr/share/gnome-panel/4.0/applets/org.gnome.applets.MultiLoadApplet.panel-applet
/usr/share/gnome-panel/4.0/applets/org.gnome.applets.NullApplet.panel-applet
/usr/share/gnome-panel/4.0/applets/org.gnome.applets.StickyNotesApplet.panel-applet
/usr/share/gnome-panel/4.0/applets/org.gnome.applets.TrashApplet.panel-applet