/lib/x86_64-linux-gnu/libply.so.4 is in libplymouth4 0.9.3-1ubuntu7.
This file is owned by root:root, with mode 0o777.
It is a symlink to /lib/x86_64-linux-gnu/libply.so.4.0.0
/lib/x86_64-linux-gnu/libply.so.4.0.0