By default, the tooltip that pops up when you hover the mouse pointer over a Ravel DRC violation in the design window does not show the Ravel violation description, but the for Ravel purposes rather less descriptive text "Externally Determined Violation". This is however possible to customize: in the menu select Setup -> Datatip Customization... to bring up the datatip customization dialog and select DRC in the Object Type list. To display the Ravel violation description, select the Advanced tab and check the Value and Save boxes of Ravel_Marker_Description. To not display "Externally Determined Violation", uncheck the Value box of Name on the General tab. Click OK, and you will see that your Ravel DRC violation tooltips have now become much more descriptive.