/usr/lib/x86_64-linux-gnu/ruby/vendor_ruby/2.3.0/IceRuby.so.35 is in ruby-zeroc-ice 3.5.1-6.4ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/ruby/vendor_ruby/2.3.0/IceRuby.so.3.5.1