This is the untethered exploit installed by the evasi0n7 jailbreaking tool. If you jailbroke you device with evasi0n7, this untether has already been automatically installed for you.
Version 0.2 of this package is what came with evasi0n7 1.0.1; it removes the TaiG splash screen and adds some features that saurik will be relying on in future updates to other packages. Users who jailbreak with evasi0n7 1.0.1 already have version 0.2 of this package installed.
If your device relies on evasi0n7 for untethering, uninstalling this package will unjailbreak your device. It will reboot in a bizarre state similar to tethered devices rebooted without using an external tool, but it will not be able to be booted tethered, so you will have to restore it with iTunes.
Please install the new untether package from the Changes tab in Cydia.
Follow iClarified on Twitter, Facebook, Google+, or RSS for further updates.