I’m looking to make some modifications to the Blueprint system to make what I think would be a useful extension. I’ve been digging through the source code but if someone could point me in the right direction I could make progress a lot faster. 
Basically what I need to know is:
- What blueprint nodes are in a graph
- The location and sizes of the blueprint nodes
- What nodes have connections to other nodes
- What controls the UI (Menu and Buttons)
- (optional) What “notch” a connection is made to.
Any suggestions on where to start looking?