This article discusses software internally used by Apple.
Acquiring a copy without Apple's consent is illegal and may result in being scammed.
This firmware is an internal NonUI build of iOS 11.0. While a seemingly earlier version of TigrisAni 15A93261h, this firmware is one of the first to be seen running on an iPhone X prototype. It is also not too well optimized for the phone's new screen, notch, and rounded corners, with parts of the screen being cut off towards the edges.
This firmware has the kernel version
Darwin Kernel Version 17.0.0: Fri Aug 11 19:50:52 PDT 2017; root:xnu_development-4570.2.5~1/DEVELOPMENT_ARM64_T8015.
Upon booting into SwitchBoard.app, the following apps are visible: