/usr/lib/x86_64-linux-gnu/libpgsbox.so is in wcslib-dev 5.16-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libpgsbox.so.5
/usr/lib/x86_64-linux-gnu/libpgsbox.so.5