/usr/lib/x86_64-linux-gnu/liblz4.so is in liblz4-dev 0.0~r122-2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/liblz4.so.1.3.0
/usr/lib/x86_64-linux-gnu/liblz4.so.1.3.0