/usr/lib/ruby/vendor_ruby/ is in ruby-safe-yaml 1.0.3-1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/ruby/vendor_ruby/safe_yaml/
/usr/lib/ruby/vendor_ruby/safe_yaml/libyaml_checker.rb
/usr/lib/ruby/vendor_ruby/safe_yaml/psych_handler.rb
/usr/lib/ruby/vendor_ruby/safe_yaml/deep.rb
/usr/lib/ruby/vendor_ruby/safe_yaml/safe_to_ruby_visitor.rb
/usr/lib/ruby/vendor_ruby/safe_yaml/syck_hack.rb
/usr/lib/ruby/vendor_ruby/safe_yaml/syck_node_monkeypatch.rb
/usr/lib/ruby/vendor_ruby/safe_yaml/psych_resolver.rb
/usr/lib/ruby/vendor_ruby/safe_yaml/syck_resolver.rb
/usr/lib/ruby/vendor_ruby/safe_yaml/transform.rb
/usr/lib/ruby/vendor_ruby/safe_yaml/parse/
/usr/lib/ruby/vendor_ruby/safe_yaml/parse/sexagesimal.rb
/usr/lib/ruby/vendor_ruby/safe_yaml/parse/date.rb
/usr/lib/ruby/vendor_ruby/safe_yaml/parse/hexadecimal.rb
/usr/lib/ruby/vendor_ruby/safe_yaml/resolver.rb
/usr/lib/ruby/vendor_ruby/safe_yaml/version.rb
/usr/lib/ruby/vendor_ruby/safe_yaml/transform/
/usr/lib/ruby/vendor_ruby/safe_yaml/transform/to_float.rb
/usr/lib/ruby/vendor_ruby/safe_yaml/transform/to_boolean.rb
/usr/lib/ruby/vendor_ruby/safe_yaml/transform/to_symbol.rb
/usr/lib/ruby/vendor_ruby/safe_yaml/transform/transformation_map.rb
/usr/lib/ruby/vendor_ruby/safe_yaml/transform/to_integer.rb
/usr/lib/ruby/vendor_ruby/safe_yaml/transform/to_date.rb
/usr/lib/ruby/vendor_ruby/safe_yaml/transform/to_nil.rb
/usr/lib/ruby/vendor_ruby/safe_yaml/load.rb
/usr/lib/ruby/vendor_ruby/safe_yaml.rb