When you run a debug build of Firefox you get a lot of stuff printed to stderr.  Some of it looks like this: ++DOCSHELL 0x7f53d836b800 == 3 ++DOMWINDOW == 5 (0x7f53d836c078) [serial = 5] [outer = (nil)] and I imagine it’s occasionally useful. You also see a lot of warnings like these, which I just … Continue reading What is the point of non-fatal assertions?