What is the HTTP Referrer Url checkbox used for?
On some browsers like Safari, Firefox, and Chrome especially in private browsing, the HTTP Referrer URL of the page was being truncated to only the domain. This was leading to URL based rule or site conditions to be erroneously evaluated.
For instance, if the page was at https://www.example.com/home/homepage the referrer URL in the request sent by the browser would only be https://www.example.com/ and thus, if the site/rule condition was to check if the URL contained the string "/home/homepage", that condition would wrongly be evaluated to false. This behaviour may also be reported for other browsers in any other conditions too, as it is dependant on the browser and its versions.
If this HTTP referrer URL setting is enabled, the referrer URL is ignored and the complete page URL is used by Engagement Engine product for rule evaluation and thus leads to the correct expected results, for both rule and site condition evaluations. The reason for introducing this checkbox was for backward compatibility as we did not want any sudden changes for existing customer's rule conditions.
The checkbox is located in the Engagement Engine rules editor under the "Settings" tab.