Filename extensions are pretty useful. They were adopted for very good reasons, and every attempt to hide them, pretend they don't matter, or otherwise make th

Filename extensions are pretty useful. They were adopted for very good reasons, and every attempt to hide them, pretend they don't matter, or otherwise make them go away has only made things worse. You still need a way to make it hard to fool people with deceptive extensions, though, and that's where the magic numbers come in.