/usr/share/doc/libvtkgdcm2-dev/changelog.Debian.gz is in libvtkgdcm2-dev 2.6.3-3ubuntu3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/libvtkgdcm2-dev/../libgdcm2.6/changelog.Debian.gz