/usr/lib/x86_64-linux-gnu/libhfstospell.so is in hfst-ospell-dev 0.4.5~r343-2.1build2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libhfstospell.so.9.0.0
/usr/lib/x86_64-linux-gnu/libhfstospell.so.9.0.0