Starting from AppDynamics 4.3, the page referrer information is no longer available by default in the browser request Analytics data. In Analytics, the page referrer is called the "Parent Page URL". The Events Service internal name for the "Parent Page URL" is pageparenturl.
Thus, when in Drag and Drop Search mode in Analytics, if you choose the event type Browser Requests and check the field Page Referrer check box, you won't see any information as shown in the screenshot below:
Likewise, in Query Language Search mode, you will not receive results when querying the field referrer from the data source browser_records:
Depending on your deployment (SaaS or on-prem), you can include the page referrer in the browser request Analytics data in one of the following ways:
INSERT INTO `eum_db`.`account_settings` (`account_name`, `key`, `value`) VALUES ('<your-eum-account-name>', 'pagePublishedWithReferrer', '.*');
INSERT INTO `eum_db`.`account_settings` (`account_name`, `key`, `value`) VALUES ('<your-eum-account-name>', 'pagePublishedWithReferrer', 'http://www.google.com');