/usr/include/gedit-3.0/ is in gedit-dev 3.4.1-0ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/gedit-3.0/gedit/
/usr/include/gedit-3.0/gedit/gedit-app-activatable.h
/usr/include/gedit-3.0/gedit/gedit-app.h
/usr/include/gedit-3.0/gedit/gedit-commands.h
/usr/include/gedit-3.0/gedit/gedit-debug.h
/usr/include/gedit-3.0/gedit/gedit-document.h
/usr/include/gedit-3.0/gedit/gedit-encodings-combo-box.h
/usr/include/gedit-3.0/gedit/gedit-encodings.h
/usr/include/gedit-3.0/gedit/gedit-message-bus.h
/usr/include/gedit-3.0/gedit/gedit-message.h
/usr/include/gedit-3.0/gedit/gedit-panel.h
/usr/include/gedit-3.0/gedit/gedit-progress-info-bar.h
/usr/include/gedit-3.0/gedit/gedit-statusbar.h
/usr/include/gedit-3.0/gedit/gedit-tab.h
/usr/include/gedit-3.0/gedit/gedit-utils.h
/usr/include/gedit-3.0/gedit/gedit-view-activatable.h
/usr/include/gedit-3.0/gedit/gedit-view.h
/usr/include/gedit-3.0/gedit/gedit-window-activatable.h
/usr/include/gedit-3.0/gedit/gedit-window.h