/usr/lib/x86_64-linux-gnu/libMRML.so is in libmrml1-dev 0.1.14+ds-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libMRML.so.1.3.0
/usr/lib/x86_64-linux-gnu/libMRML.so.1.3.0