/usr/lib/libmonoboehm-2.0.so is in libmonoboehm-2.0-dev 3.2.8+dfsg-4ubuntu1.1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/libmonoboehm-2.0.so.1.0.0
/usr/lib/libmonoboehm-2.0.so.1.0.0