/usr/share/gtk-doc/html/ is in libxfce4ui-1-dev 4.8.1-1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/gtk-doc/html/libxfce4ui/
/usr/share/gtk-doc/html/libxfce4ui/XfceSMClient.html
/usr/share/gtk-doc/html/libxfce4ui/home.png
/usr/share/gtk-doc/html/libxfce4ui/index.html
/usr/share/gtk-doc/html/libxfce4ui/index.sgml
/usr/share/gtk-doc/html/libxfce4ui/ix01.html
/usr/share/gtk-doc/html/libxfce4ui/left.png
/usr/share/gtk-doc/html/libxfce4ui/libxfce4ui-extensions.html
/usr/share/gtk-doc/html/libxfce4ui/libxfce4ui-fundamentals.html
/usr/share/gtk-doc/html/libxfce4ui/libxfce4ui-introduction.html
/usr/share/gtk-doc/html/libxfce4ui/libxfce4ui-libxfce4ui-config.html
/usr/share/gtk-doc/html/libxfce4ui/libxfce4ui-sm.html
/usr/share/gtk-doc/html/libxfce4ui/libxfce4ui-widgets.html
/usr/share/gtk-doc/html/libxfce4ui/libxfce4ui-xfce-dialogs.html
/usr/share/gtk-doc/html/libxfce4ui/libxfce4ui-xfce-gdk-extensions.html
/usr/share/gtk-doc/html/libxfce4ui/libxfce4ui-xfce-gtk-extensions.html
/usr/share/gtk-doc/html/libxfce4ui/libxfce4ui-xfce-spawn.html
/usr/share/gtk-doc/html/libxfce4ui/libxfce4ui-xfce-titled-dialog.html
/usr/share/gtk-doc/html/libxfce4ui/libxfce4ui.devhelp2
/usr/share/gtk-doc/html/libxfce4ui/right.png
/usr/share/gtk-doc/html/libxfce4ui/style.css
/usr/share/gtk-doc/html/libxfce4ui/up.png