/usr/share/doc/libwayland-client0-dbg/changelog.Debian.gz is in libwayland-client0-dbg 1.4.0-1ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/libwayland-client0-dbg/../libwayland-client0/changelog.Debian.gz