/usr/lib/x86_64-linux-gnu/libIlmImf.so.6 is in libopenexr6 1.6.1-7ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libIlmImf.so.6.0.0
/usr/lib/x86_64-linux-gnu/libIlmImf.so.6.0.0