I'm running Kubuntu 12.04. Like many others, I often get the message on startup "An application has crashed on your system (now or in the past)." This message is obviously completely unrevealing. But I do know how to find what's causing it: look in apport.log.
The bug I want to report is simply that the error message is inappropriate and should specifically advise looking in apport.log. But I haven't been able to figure out how to report this bug.