External Node

An External Node (also formerly known as an XNode, not to be confused with the current meaning of that term) is a subVI whose code determines not only its function, but also its edit-time appearance and behavior. They are similar to modern XNodes in this respect, but while an XNode is a library containing several Ability VI's, an External Node is a single VI containing a case for each ability. The name of an External Node VI must begin with the characters ";D", not including quotes.

Much like XNodes, External Nodes are not an officially-supported technology for third-party development.