/usr/lib/x86_64-linux-gnu/libplds4.so.0d is in libnspr4-0d 4.8.9-1ubuntu2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libplds4.so
/usr/lib/x86_64-linux-gnu/libplds4.so