Sightglass is an application in SwitchBoard that has shown up on newer prototype devices, including an iPhone 6. It is known to be used for launching diagnostics-related scripts. The icon of the app was the logo of a coffee shop in San Francisco called Sightglass Coffee, however it has since been changed to a 3x3 grid of colored dots on a brown background.
On watchOS, SwitchBoard is not present and apps are launched from Sightglass. It retains the ability to run scripts, and can also be used to power off or restart the device, as well as setting whether the display should be kept on or not.
Contents of the App (iPhone):
ChicagoFLF.ttf Sightglass _CodeSignature. _internal_reset_pedometer.png Info.plist Sightglass-Apps.plist _internal_apps.png. _internal_scripts.png PkgInfo. Sightglass-BootTasks.plist _internal_get_pedometer.png _internal_sightglass.png ResourceRules.plist Sightglass-Help.plist _internal_help.png com.apple.osdiags.Sightglass.plist