I'm sure there's lots of folks out there who know all about this, but I didn't, so I thought I'd share. When trying to debug a nasty issue sometimes you've got to get creative and even employ some "magic" to help get to the root of the problem and that is exactly what Tech Note 2124 is all about. As Apple puts it:
This technote describes a number of 'secret' debugging facilities in Mac OS X, including environment variables, preferences, routines callable from GDB, special files, and so on. If you're developing for Mac OS X, you should look through this list to see if you're missing out on something that will make your life easier.Thanks to Jesse for sending me this gem.