/usr/lib/x86_64-linux-gnu/libNGmath.so is in libncarg-dev 6.2.0-3+b1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libNGmath.so.1
/usr/lib/x86_64-linux-gnu/libNGmath.so.1