BurnIn

"Drag To Unlock" screen. Text is "Drag To Unlock" and "Shut Down"

After "Drag To Unlock" screen, when you "Drag To Unlock", you get this screen. In order, "Start Burnin", "Reset Test Enviroment", and "Quit"

???

Burnin is codename for the (supposed) diagnostics firmware used when iPhones are sent in to Apple for repair. Unfortunately, not much is known about this mysterious "Burnin". It is probably a ramdisk.