/usr/share/doc/linux-image-extra-4.11.0-1015-azure/changelog.Debian.gz is in linux-image-extra-4.11.0-1015-azure 4.11.0-1015.15.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/linux-image-extra-4.11.0-1015-azure/../linux-image-4.11.0-1015-azure/changelog.Debian.gz