/usr/share/gtk-doc/html/gdl-3.0/ is in libgdl-3-doc 3.8.1-2ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/gtk-doc/html/gdl-3.0/GdlDock.html
/usr/share/gtk-doc/html/gdl-3.0/GdlDockBar.html
/usr/share/gtk-doc/html/gdl-3.0/GdlDockItem.html
/usr/share/gtk-doc/html/gdl-3.0/GdlDockItemButtonImage.html
/usr/share/gtk-doc/html/gdl-3.0/GdlDockItemGrip.html
/usr/share/gtk-doc/html/gdl-3.0/GdlDockLayout.html
/usr/share/gtk-doc/html/gdl-3.0/GdlDockMaster.html
/usr/share/gtk-doc/html/gdl-3.0/GdlDockNotebook.html
/usr/share/gtk-doc/html/gdl-3.0/GdlDockObject.html
/usr/share/gtk-doc/html/gdl-3.0/GdlDockPaned.html
/usr/share/gtk-doc/html/gdl-3.0/GdlDockPlaceholder.html
/usr/share/gtk-doc/html/gdl-3.0/GdlDockTablabel.html
/usr/share/gtk-doc/html/gdl-3.0/GdlPreviewWindow.html
/usr/share/gtk-doc/html/gdl-3.0/GdlSwitcher.html
/usr/share/gtk-doc/html/gdl-3.0/annotation-glossary.html
/usr/share/gtk-doc/html/gdl-3.0/api-index-full.html
/usr/share/gtk-doc/html/gdl-3.0/api.html
/usr/share/gtk-doc/html/gdl-3.0/core.html
/usr/share/gtk-doc/html/gdl-3.0/deprecated.html
/usr/share/gtk-doc/html/gdl-3.0/gdl-3.0.devhelp2
/usr/share/gtk-doc/html/gdl-3.0/home.png
/usr/share/gtk-doc/html/gdl-3.0/index.html
/usr/share/gtk-doc/html/gdl-3.0/index.sgml
/usr/share/gtk-doc/html/gdl-3.0/left.png
/usr/share/gtk-doc/html/gdl-3.0/private.html
/usr/share/gtk-doc/html/gdl-3.0/right.png
/usr/share/gtk-doc/html/gdl-3.0/style.css
/usr/share/gtk-doc/html/gdl-3.0/up.png
/usr/share/gtk-doc/html/gdl-3.0/widget.html