/usr/lib/ruby/ is in ruby-raindrops 0.17.0-1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/ruby/vendor_ruby/
/usr/lib/ruby/vendor_ruby/raindrops/
/usr/lib/ruby/vendor_ruby/raindrops/aggregate/
/usr/lib/ruby/vendor_ruby/raindrops/aggregate/last_data_recv.rb
/usr/lib/ruby/vendor_ruby/raindrops/aggregate/pmq.rb
/usr/lib/ruby/vendor_ruby/raindrops/aggregate.rb
/usr/lib/ruby/vendor_ruby/raindrops/last_data_recv.rb
/usr/lib/ruby/vendor_ruby/raindrops/linux.rb
/usr/lib/ruby/vendor_ruby/raindrops/middleware/
/usr/lib/ruby/vendor_ruby/raindrops/middleware/proxy.rb
/usr/lib/ruby/vendor_ruby/raindrops/middleware.rb
/usr/lib/ruby/vendor_ruby/raindrops/struct.rb
/usr/lib/ruby/vendor_ruby/raindrops/watcher.rb
/usr/lib/ruby/vendor_ruby/raindrops.rb