/usr/share/doc/libcollectdclient-dev/README.Debian.gz is in libcollectdclient-dev 5.4.0-3ubuntu2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/libcollectdclient-dev/../libcollectdclient1/README.Debian.gz