SwitchBoard.app is one of Apple's internal utilities. It's a simple launcher of other utilities. Generally, it's the same set of applications (new test apps are created to test new features). It's usually located in the /AppleInternal/Applications folder along other internal applications. It usually finds the applications it needs to load in
/AppleInternal/Applications/SwitchBoard/.Currently, there is no SwitchBoard binary available for public.
SwitchBoard and diagnostic utilities are copied onto the device during restore from special firmware bundles which are seeded only to Apple official service centers. It may be installed onto devices through PurpleRestore. Switchboard and its internal utilities are, in fact, present on all iDevices during manufacturing. The utilities run extensive tests on the devices, including sensors, thermal measurements and more - and only when all tests pass do the devices go through a final stage, which involves removing the debug utilities and installing the stock version of iOS.
iPad running SwitchBoard
The file structure of SwitchBoard.app:
Entitlements.plist SwitchBoard Info.plist SwitchBoard-Settings.plist PkgInfo _CodeSignature ResourceRules.plist com.apple.SwitchBoard.plist