The rendered graphs are not guaranteed at all to reflect what the code actually does.

These graphs are rendered by, let loose on all .c files found in the osmocom core network and BSS repositories.

To detect state transitions and so fort, uses highly speculative regex evaluation depending on coding style. So it's just a hack to help getting an overview of what might be happening, so that you can more easily pinpoint places in the code to go and look at what it is actually doing.