/usr/share/doc/libmysqlcppconn-dev/changelog.Debian.gz is in libmysqlcppconn-dev 1.1.9-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/libmysqlcppconn-dev/../libmysqlcppconn7v5/changelog.Debian.gz