/usr/lib/x86_64-linux-gnu/libphysfs.so is in libphysfs-dev 2.0.3-2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libphysfs.so.1
/usr/lib/x86_64-linux-gnu/libphysfs.so.1