This article discusses software internally used by Apple.
Acquiring a copy without Apple's consent is illegal and may result in being scammed.
Unlike previous NonUI 7.0 firmwares such as InnsbruckNanshan 11A24581c, this firmware does not have MesaCal to test the Touch ID sensor. The reason why it is hidden or removed is currently unknown. It does, however, have Operator instead, along with a few others on SwitchBoard.app: