The question of where a custom node comes from comes up on the forums pretty often, so I figured it was time for a solution. Well thanks to dynamonodes.com we now have an index for most packages available on the package manager.
https://screencast.autodesk.com/Embed/Timeline/4562c4e0-e882-4a6a-83b8-09a0f8d5ecdd
Source: http://sixtysecondrevit.blogspot.com/2016/05/dynamobim-what-node.html
*Edit – I went ahead and published this as its own package as well to enable easier location of this node.
Dynamo Nodes 
Great job John. One thought: sometimes a node name can be duplicated across different packages. Can you make another output that lists all possible packages the node is from?
I’ll do some digging. The thought was it would give you the most likely. But maybe another output with other candidates is in order.