All the nodes you can use into a graph, and that are NOT atomic nodes, are called graph instances.
They are just graphs embedded into a node that you can use into another graph.
In the graph view, you can distinguish a graph instance by its dark red title color:
Graph instances have common attributes, even if some of them may or may not be filled depending of the Author of the graph.
New in SD 2017: displays the path of the original graph (the top right icon will open the Windows explorer to the folder containing the graph.
Displays the package internal resource reference path
Description, categories and other information
Information provided by the author of the original graph: