/usr/lib/ruby/vendor_ruby/active_support/core_ext/string/ is in ruby-activesupport-2.3 2.3.14-7.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/ruby/vendor_ruby/active_support/core_ext/string/access.rb
/usr/lib/ruby/vendor_ruby/active_support/core_ext/string/behavior.rb
/usr/lib/ruby/vendor_ruby/active_support/core_ext/string/bytesize.rb
/usr/lib/ruby/vendor_ruby/active_support/core_ext/string/conversions.rb
/usr/lib/ruby/vendor_ruby/active_support/core_ext/string/filters.rb
/usr/lib/ruby/vendor_ruby/active_support/core_ext/string/inflections.rb
/usr/lib/ruby/vendor_ruby/active_support/core_ext/string/iterators.rb
/usr/lib/ruby/vendor_ruby/active_support/core_ext/string/multibyte.rb
/usr/lib/ruby/vendor_ruby/active_support/core_ext/string/output_safety.rb
/usr/lib/ruby/vendor_ruby/active_support/core_ext/string/starts_ends_with.rb
/usr/lib/ruby/vendor_ruby/active_support/core_ext/string/xchar.rb