/usr/lib/ruby/ is in ruby-stomp 1.3.5-1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/ruby/vendor_ruby/
/usr/lib/ruby/vendor_ruby/stomp/
/usr/lib/ruby/vendor_ruby/stomp/message.rb
/usr/lib/ruby/vendor_ruby/stomp/slogger.rb
/usr/lib/ruby/vendor_ruby/stomp/null_logger.rb
/usr/lib/ruby/vendor_ruby/stomp/errors.rb
/usr/lib/ruby/vendor_ruby/stomp/connection.rb
/usr/lib/ruby/vendor_ruby/stomp/constants.rb
/usr/lib/ruby/vendor_ruby/stomp/sslparams.rb
/usr/lib/ruby/vendor_ruby/stomp/version.rb
/usr/lib/ruby/vendor_ruby/stomp/client.rb
/usr/lib/ruby/vendor_ruby/stomp/ext/
/usr/lib/ruby/vendor_ruby/stomp/ext/hash.rb
/usr/lib/ruby/vendor_ruby/stomp/codec.rb
/usr/lib/ruby/vendor_ruby/connection/
/usr/lib/ruby/vendor_ruby/connection/netio.rb
/usr/lib/ruby/vendor_ruby/connection/utf8.rb
/usr/lib/ruby/vendor_ruby/connection/utils.rb
/usr/lib/ruby/vendor_ruby/connection/heartbeats.rb
/usr/lib/ruby/vendor_ruby/stomp.rb
/usr/lib/ruby/vendor_ruby/client/
/usr/lib/ruby/vendor_ruby/client/utils.rb