/usr/share/doc/gir1.2-gtksource-3.0/NEWS.gz is in gir1.2-gtksource-3.0 3.4.1-0ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/gir1.2-gtksource-3.0/../libgtksourceview-3.0-0/NEWS.gz