/usr/lib/x86_64-linux-gnu/libgtkdataboxmm-0.9.so is in libgtkdataboxmm-dev 0.9.4-3build1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libgtkdataboxmm-0.9.so.0.0.2
/usr/lib/x86_64-linux-gnu/libgtkdataboxmm-0.9.so.0.0.2