/usr/share/doc/libgmime-2.6-dev/changelog.Debian.gz is in libgmime-2.6-dev 2.6.20-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/libgmime-2.6-dev/../libgmime-2.6-0/changelog.Debian.gz