Some time ago, I noted that If you're looking for the code that displays a particular dialog box, the most directly way to find it is to look for the dialog box. That works if you have a screen shot of the dialog box. But what if you don't?
A colleague of mine wanted to find the code that displays the "Your password is going to expire soon" notification, but he didn't know what string to look for. It so happened that he asked me four hours too late, because my password happened to have expired that morning, but by the time he asked me for the text of the message, I had already changed my password.
Think out of the box: You know who probably has a screen shot of the "your password is going to expire soon" notification? Somebody on the Internet.
A Web image search quickly turned up the exact text.