/usr/share/doc/libmumps-scotch-dev/changelog.Debian.gz is in libmumps-scotch-dev 5.1.2-4.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/libmumps-scotch-dev/../libmumps-5.1.2/changelog.Debian.gz