This is a code plugin that introduces the graph data structure to Unreal. It's currently in early stages as there's only one type of graph supported - the unweighted bidirectional graph. Other types are in the works!
The graph is C++ and Blueprints compatible since its base C++ class is UObject. To use the structure simply construct an object of it using the NewObject function in C++ or the Construct node in Blueprints. After that you can add nodes and edges that are represented by the Graph Node and Graph Edge structures respectively.