Those are for use from a Graph conference application which I demo'd at Engage. Some of the code for that is in the source code, in org.openntf.domino package, in src/sample/java. The org.openntf.conference.graph package has the classes for each vertex element as well as an initialiser to load data for Engage 2015 (EngageDataInitializer) and from IBM ConnectED local database (DataInitializer). There are some examples. I found some issues prior to ICON UK that required a fix to ConferenceGraph class, I'm not sure if they were committed to my branch in time though. But the source code demonstrates the graph database approach. The source code for the app itself is part of the CrossWorlds repository
https://github.com/paulswithers/CrossWorlds/tree/paul_development. We'll be continuing development of that app to provide an app for IBM Connect 2016 and I'll be publishing that also as an OSGi application (similar to what I've done with Key Dates app) and possibly blogging about it too.
It's a non-XPages application and, even when populated, you won't see any documents in it, because the view design is set to return false.