/usr/lib/ruby/ is in ruby-validatable 1.6.7-9.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/ruby/vendor_ruby/
/usr/lib/ruby/vendor_ruby/validatable/
/usr/lib/ruby/vendor_ruby/validatable/validations/
/usr/lib/ruby/vendor_ruby/validatable/validations/validation_base.rb
/usr/lib/ruby/vendor_ruby/validatable/validations/validates_acceptance_of.rb
/usr/lib/ruby/vendor_ruby/validatable/validations/validates_confirmation_of.rb
/usr/lib/ruby/vendor_ruby/validatable/validations/validates_numericality_of.rb
/usr/lib/ruby/vendor_ruby/validatable/validations/validates_length_of.rb
/usr/lib/ruby/vendor_ruby/validatable/validations/validates_format_of.rb
/usr/lib/ruby/vendor_ruby/validatable/validations/validates_each.rb
/usr/lib/ruby/vendor_ruby/validatable/validations/validates_true_for.rb
/usr/lib/ruby/vendor_ruby/validatable/validations/validates_presence_of.rb
/usr/lib/ruby/vendor_ruby/validatable/errors.rb
/usr/lib/ruby/vendor_ruby/validatable/object_extension.rb
/usr/lib/ruby/vendor_ruby/validatable/macros.rb
/usr/lib/ruby/vendor_ruby/validatable/requireable.rb
/usr/lib/ruby/vendor_ruby/validatable/child_validation.rb
/usr/lib/ruby/vendor_ruby/validatable/validatable_instance_methods.rb
/usr/lib/ruby/vendor_ruby/validatable/understandable.rb
/usr/lib/ruby/vendor_ruby/validatable/validatable_class_methods.rb
/usr/lib/ruby/vendor_ruby/validatable/included_validation.rb
/usr/lib/ruby/vendor_ruby/validatable.rb