/usr/share/doc/libpocofoundation9v5-dbg/changelog.Debian.gz is in libpocofoundation9v5-dbg 1.3.6p1-5.1build1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/libpocofoundation9v5-dbg/../libpocofoundation9v5/changelog.Debian.gz