An undocumented feature of _satellite.getVar in DTM was the ability to pull a value from the event object of event-based rules. This feature was seldom used becuase at some point, DTM began proving event as a free variable in these contexts.
If you see this usage in the custom code of your DTM implementation, you should be able to simply reference the event object directly.
//Crusty old DTM way
var linkTarget = _satellite.getVar("event.target");