/usr/share/gtk-doc/html/libgrip is in libgrip-dev 0.3.7+14.04.20140303-0ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/gtk-doc/html/../../doc/libgrip-dev/html
/usr/share/gtk-doc/html/../../doc/libgrip-dev/html