Rule variable name. It should match the corresponding key name fired by the pixel. A name must begin with US-ascii letters or underscore or UTF8 code that is greater than 127 and consist of US-ascii letters or digits or underscore or UTF8 code that is greater than 127. For websites, there are two built-in variable URL (name = 'url__') and referrer URL (name = 'ref_url__'). This field must be populated when creating a new rule item.
rule_item. An atomic rule item. rule_item can be only one of the following: