/usr/lib/ is in ruby-ice-nine 0.11.1-1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/ruby/
/usr/lib/ruby/vendor_ruby/
/usr/lib/ruby/vendor_ruby/ice_nine/
/usr/lib/ruby/vendor_ruby/ice_nine/freezer/
/usr/lib/ruby/vendor_ruby/ice_nine/freezer/nil_class.rb
/usr/lib/ruby/vendor_ruby/ice_nine/freezer/numeric.rb
/usr/lib/ruby/vendor_ruby/ice_nine/freezer/range.rb
/usr/lib/ruby/vendor_ruby/ice_nine/freezer/false_class.rb
/usr/lib/ruby/vendor_ruby/ice_nine/freezer/true_class.rb
/usr/lib/ruby/vendor_ruby/ice_nine/freezer/symbol.rb
/usr/lib/ruby/vendor_ruby/ice_nine/freezer/hash/
/usr/lib/ruby/vendor_ruby/ice_nine/freezer/hash/state.rb
/usr/lib/ruby/vendor_ruby/ice_nine/freezer/object.rb
/usr/lib/ruby/vendor_ruby/ice_nine/freezer/hash.rb
/usr/lib/ruby/vendor_ruby/ice_nine/freezer/struct.rb
/usr/lib/ruby/vendor_ruby/ice_nine/freezer/module.rb
/usr/lib/ruby/vendor_ruby/ice_nine/freezer/rubinius.rb
/usr/lib/ruby/vendor_ruby/ice_nine/freezer/array.rb
/usr/lib/ruby/vendor_ruby/ice_nine/freezer/no_freeze.rb
/usr/lib/ruby/vendor_ruby/ice_nine/support/
/usr/lib/ruby/vendor_ruby/ice_nine/support/recursion_guard.rb
/usr/lib/ruby/vendor_ruby/ice_nine/core_ext/
/usr/lib/ruby/vendor_ruby/ice_nine/core_ext/object.rb
/usr/lib/ruby/vendor_ruby/ice_nine/freezer.rb
/usr/lib/ruby/vendor_ruby/ice_nine/version.rb
/usr/lib/ruby/vendor_ruby/ice_nine.rb