/usr/share/doc/libpion-net-4.0/changelog.Debian.gz is in libpion-net-4.0 4.0.7+dfsg-3.1ubuntu2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/libpion-net-4.0/../libpion-common-4.0/changelog.Debian.gz