/usr/lib/x86_64-linux-gnu/liboctinterp.so is in liboctave-dev 3.8.1-1ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/liboctinterp.so.2.0.0
/usr/lib/x86_64-linux-gnu/liboctinterp.so.2.0.0