/usr/share/doc/gdc-6-s390x-linux-gnu/README.Bugs is in gdc-6-s390x-linux-gnu 6.4.0-17ubuntu1cross1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/gdc-6-s390x-linux-gnu/../gcc-6-s390x-linux-gnu/README.Bugs