/usr/share/doc/gir1.2-gstreamer-1.0/README.Debian is in gir1.2-gstreamer-1.0 1.14.0-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/gir1.2-gstreamer-1.0/../libgstreamer1.0-0/README.Debian