/usr/share/doc/gdc-mips64-linux-gnuabi64/changelog.Debian.gz is in gdc-mips64-linux-gnuabi64 4:5.3.1-1ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/gdc-mips64-linux-gnuabi64/../cpp-mips64-linux-gnuabi64/changelog.Debian.gz