/usr/lib/ruby/vendor_ruby/em/protocols/ is in ruby-eventmachine 1.0.3-4.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/ruby/vendor_ruby/em/protocols/header_and_content.rb
/usr/lib/ruby/vendor_ruby/em/protocols/httpclient.rb
/usr/lib/ruby/vendor_ruby/em/protocols/httpclient2.rb
/usr/lib/ruby/vendor_ruby/em/protocols/line_and_text.rb
/usr/lib/ruby/vendor_ruby/em/protocols/line_protocol.rb
/usr/lib/ruby/vendor_ruby/em/protocols/linetext2.rb
/usr/lib/ruby/vendor_ruby/em/protocols/memcache.rb
/usr/lib/ruby/vendor_ruby/em/protocols/object_protocol.rb
/usr/lib/ruby/vendor_ruby/em/protocols/postgres3.rb
/usr/lib/ruby/vendor_ruby/em/protocols/saslauth.rb
/usr/lib/ruby/vendor_ruby/em/protocols/smtpclient.rb
/usr/lib/ruby/vendor_ruby/em/protocols/smtpserver.rb
/usr/lib/ruby/vendor_ruby/em/protocols/socks4.rb
/usr/lib/ruby/vendor_ruby/em/protocols/stomp.rb
/usr/lib/ruby/vendor_ruby/em/protocols/tcptest.rb