Recently trap processing script was created. It has node $node, $trap as a string and $varbinds as SNMP_VarBind, event that is about to be generated is accessible via $event global variable.
You can iterate over $node->children, find macAddr and get description. And using method addParameter add one more parameter to event.
Documentation: https://www.netxms.org/documentation/nxsl-3.2/
Some NXSL example available on wiki
			You can iterate over $node->children, find macAddr and get description. And using method addParameter add one more parameter to event.
Documentation: https://www.netxms.org/documentation/nxsl-3.2/
Some NXSL example available on wiki