The UML specification is 796 pages[0]. It is amazing how humanity can take simple concepts like flow charts and inflate them into insane, hyper detailed legalistic rule books that almost no one understands or uses.
/sarcasm
13.5.11 A_signal_signalEvent [Association]
...that thing. These are men who really, really wanted to be on the PL/1 committee so many years ago. They missed their calling, like so many of us.