Abstract Content Object. Received in an array when calling content_objects.[:content_type_name] on Site
content_object.referenced_in_[content_type]_as_[content_field]
If the content_object is referenced elsewhere, you can query on which objects by calling this. E.g. when the content_object is referenced from a reference ContentField named categories on another ContentType named blog_posts, you would call content_object.referenced_in_blog_posts_as_categories. Which would return all Blog Posts where the content_object was referenced as a category.