/usr/share/gazebo-9/media/gui/fonts/DejaVuSans.ttf is in gazebo9-common 9.0.0+dfsg5-3ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/gazebo-9/media/gui/fonts/../../../../fonts/truetype/dejavu/DejaVuSans.ttf