/usr/lib/x86_64-linux-gnu/libruby-2.5.so is in ruby2.5-dev 2.5.1-1ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libruby-2.5.so.2.5.1
/usr/lib/x86_64-linux-gnu/libruby-2.5.so.2.5.1