/usr/share/help/el/gdm/legal.xml is in gdm3 3.28.0-0ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/help/el/gdm/../../../help-langpack/el/gdm/legal.xml
/usr/share/help/el/gdm/../../../help-langpack/el/gdm/legal.xml