/usr/lib/x86_64-linux-gnu/libexpect.so is in tcl-expect-dev 5.45-7+deb9u1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libexpect.so.5.45
/usr/lib/x86_64-linux-gnu/libexpect.so.5.45