There's no documentation for this item.

Source Code

# File active_support/core_ext/module/inclusion.rb, line 2
def included_in_classes
  classes = []
  ObjectSpace.each_object(Class) { |k| classes << k if k.included_modules.include?(self) }

  classes.reverse.inject([]) do |unique_classes, klass| 
    unique_classes << klass unless unique_classes.collect { |k| k.to_s }.include?(klass.to_s)
    unique_classes
  end
end