/usr/lib/ is in unicorn 5.2.0-1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/ruby/
/usr/lib/ruby/vendor_ruby/
/usr/lib/ruby/vendor_ruby/unicorn/
/usr/lib/ruby/vendor_ruby/unicorn/app/
/usr/lib/ruby/vendor_ruby/unicorn/app/old_rails/
/usr/lib/ruby/vendor_ruby/unicorn/app/old_rails/static.rb
/usr/lib/ruby/vendor_ruby/unicorn/app/old_rails.rb
/usr/lib/ruby/vendor_ruby/unicorn/cgi_wrapper.rb
/usr/lib/ruby/vendor_ruby/unicorn/configurator.rb
/usr/lib/ruby/vendor_ruby/unicorn/const.rb
/usr/lib/ruby/vendor_ruby/unicorn/http_request.rb
/usr/lib/ruby/vendor_ruby/unicorn/http_response.rb
/usr/lib/ruby/vendor_ruby/unicorn/http_server.rb
/usr/lib/ruby/vendor_ruby/unicorn/launcher.rb
/usr/lib/ruby/vendor_ruby/unicorn/oob_gc.rb
/usr/lib/ruby/vendor_ruby/unicorn/preread_input.rb
/usr/lib/ruby/vendor_ruby/unicorn/socket_helper.rb
/usr/lib/ruby/vendor_ruby/unicorn/stream_input.rb
/usr/lib/ruby/vendor_ruby/unicorn/tee_input.rb
/usr/lib/ruby/vendor_ruby/unicorn/tmpio.rb
/usr/lib/ruby/vendor_ruby/unicorn/util.rb
/usr/lib/ruby/vendor_ruby/unicorn/version.rb
/usr/lib/ruby/vendor_ruby/unicorn/worker.rb
/usr/lib/ruby/vendor_ruby/unicorn.rb
/usr/lib/x86_64-linux-gnu/
/usr/lib/x86_64-linux-gnu/ruby/
/usr/lib/x86_64-linux-gnu/ruby/vendor_ruby/
/usr/lib/x86_64-linux-gnu/ruby/vendor_ruby/2.3.0/
/usr/lib/x86_64-linux-gnu/ruby/vendor_ruby/2.3.0/unicorn_http.so