Custom URL reports allow you to link to URLs that are accessible, either outside of the ExtraView environment or inside the ExtraView environment. There are limitations on reaching URLs outside of the domain within which you are working, set and controlled by security constraints within your browser.
If you create an absolute path to a URL outside of ExtraView, when you run the report ExtraView opens a window with the report (unless it is placed on the Home Page, in which case the URL is opened within the Home Page). If custom code is used in conjunction with a custom URL report, you may set filters that can programmatically be passed to the report.
Reference
Additional information: http://docs.extraview.com/extraview-23/end-user-guide/reporting/report-types/custom-url-reports