/usr/bin/grub-ntldr-img is in grub-pc 2.02~beta2-9ubuntu1.6.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/bin/../lib/grub/i386-pc/grub-ntldr-img
/usr/bin/../lib/grub/i386-pc/grub-ntldr-img