What does the number pair mean in the output of NSException?

Question

Sorry, I'm afraid this question is fairly ambiguous but I don't know the correct terminology to use. Maybe someone could edit it?

I'm trying to fathom what this problem is

2012-12-23 09:53:36.827 myApp[10768:303] *** -[__NSArrayM objectAtIndex:]: index 13 beyond bounds for empty array

does the number pair in squard brackets refer to a line number or something?

Answer 1

These are [processId:logging thread's Mach port]