/usr/lib/x86_64-linux-gnu/libdSFMT-521.so.1 is in libdsfmt-521-1 2.2.3+dfsg-3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libdSFMT-521.so.1.0.0
/usr/lib/x86_64-linux-gnu/libdSFMT-521.so.1.0.0