/usr/share/doc/libgpp4f-dev/changelog.Debian.gz is in libgpp4f-dev 1.3.1-0ubuntu5.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/libgpp4f-dev/../libgpp4-0/changelog.Debian.gz
/usr/share/doc/libgpp4f-dev/../libgpp4-0/changelog.Debian.gz