/usr/share/man/man8/kvm-nbd.8.gz is in qemu-utils 1.0+noroms-0ubuntu14.31.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/man/man8/qemu-nbd.8.gz
/usr/share/man/man8/qemu-nbd.8.gz