/usr/lib/ruby/vendor_ruby/ is in ruby-riot 0.12.7-1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/ruby/vendor_ruby/riot.rb
/usr/lib/ruby/vendor_ruby/riot/
/usr/lib/ruby/vendor_ruby/riot/context_options.rb
/usr/lib/ruby/vendor_ruby/riot/context_helpers.rb
/usr/lib/ruby/vendor_ruby/riot/context.rb
/usr/lib/ruby/vendor_ruby/riot/message.rb
/usr/lib/ruby/vendor_ruby/riot/version.rb
/usr/lib/ruby/vendor_ruby/riot/assertion_macros/
/usr/lib/ruby/vendor_ruby/riot/assertion_macros/empty.rb
/usr/lib/ruby/vendor_ruby/riot/assertion_macros/kind_of.rb
/usr/lib/ruby/vendor_ruby/riot/assertion_macros/assigns.rb
/usr/lib/ruby/vendor_ruby/riot/assertion_macros/raises_kind_of.rb
/usr/lib/ruby/vendor_ruby/riot/assertion_macros/respond_to.rb
/usr/lib/ruby/vendor_ruby/riot/assertion_macros/exists.rb
/usr/lib/ruby/vendor_ruby/riot/assertion_macros/size.rb
/usr/lib/ruby/vendor_ruby/riot/assertion_macros/raises.rb
/usr/lib/ruby/vendor_ruby/riot/assertion_macros/equals.rb
/usr/lib/ruby/vendor_ruby/riot/assertion_macros/nil.rb
/usr/lib/ruby/vendor_ruby/riot/assertion_macros/same_elements.rb
/usr/lib/ruby/vendor_ruby/riot/assertion_macros/includes.rb
/usr/lib/ruby/vendor_ruby/riot/assertion_macros/matches.rb
/usr/lib/ruby/vendor_ruby/riot/assertion_macros/equivalent_to.rb
/usr/lib/ruby/vendor_ruby/riot/assertion_macros/any.rb
/usr/lib/ruby/vendor_ruby/riot/reporter.rb
/usr/lib/ruby/vendor_ruby/riot/runnable.rb
/usr/lib/ruby/vendor_ruby/riot/assertion_macro.rb
/usr/lib/ruby/vendor_ruby/riot/rr.rb
/usr/lib/ruby/vendor_ruby/riot/middleware.rb
/usr/lib/ruby/vendor_ruby/riot/assertion.rb
/usr/lib/ruby/vendor_ruby/riot/reporter/
/usr/lib/ruby/vendor_ruby/riot/reporter/io.rb
/usr/lib/ruby/vendor_ruby/riot/reporter/story.rb
/usr/lib/ruby/vendor_ruby/riot/reporter/silent.rb
/usr/lib/ruby/vendor_ruby/riot/reporter/pretty_dot_matrix.rb
/usr/lib/ruby/vendor_ruby/riot/reporter/dot_matrix.rb
/usr/lib/ruby/vendor_ruby/riot/situation.rb