/lib/x86_64-linux-gnu/libreadline.so.7 is in libreadline7 7.0-3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /lib/x86_64-linux-gnu/libreadline.so.7.0
/lib/x86_64-linux-gnu/libreadline.so.7.0