/usr/lib/ruby/vendor_ruby/ is in ruby-em-hiredis 0.3.1-1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/ruby/vendor_ruby/em-hiredis/
/usr/lib/ruby/vendor_ruby/em-hiredis/base_client.rb
/usr/lib/ruby/vendor_ruby/em-hiredis/client.rb
/usr/lib/ruby/vendor_ruby/em-hiredis/connection.rb
/usr/lib/ruby/vendor_ruby/em-hiredis/event_emitter.rb
/usr/lib/ruby/vendor_ruby/em-hiredis/lock.rb
/usr/lib/ruby/vendor_ruby/em-hiredis/lock_lua/
/usr/lib/ruby/vendor_ruby/em-hiredis/lock_lua/lock_acquire.lua
/usr/lib/ruby/vendor_ruby/em-hiredis/lock_lua/lock_release.lua
/usr/lib/ruby/vendor_ruby/em-hiredis/persistent_lock.rb
/usr/lib/ruby/vendor_ruby/em-hiredis/pubsub_client.rb
/usr/lib/ruby/vendor_ruby/em-hiredis/version.rb
/usr/lib/ruby/vendor_ruby/em-hiredis.rb