/usr/share/doc/libtk8.6-dbg/changelog.Debian.gz is in libtk8.6-dbg 8.6.1-3ubuntu2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/libtk8.6-dbg/../libtk8.6/changelog.Debian.gz
/usr/share/doc/libtk8.6-dbg/../libtk8.6/changelog.Debian.gz