Ridiculously overcomplicated, and almost entirely unique to GNUnet:

https://gnunet.org/en/architecture.html

My uncharitable guess would be that most of it is completely unusable outside the context of this project.

It might look complicated at first, but the parts seem reasonable too me. It might be simpler to understand when the building blocks are grouped and larger components only show top level (grouped) dependencies instead of the full graph.

I just needed one peek at that crazy diagram to agree with your point.