Trampoline

Trampoline is the codename for the iPhone 5's OTA Update Enabler. iOS 6.0 on the iPhone 5 apparently included a bug that prevented OTA updates from occurring properly. As a result, Apple made the OTA update process a little less straightforward.

Trying to perform an OTA update informs you about the updater app, and how to obtain it.

Process

Spawn by update daemon (causes elevated privileges)
Mount Disk Image /Applications/iOSUpdater.app/iOSUpdaterHelper.dmg at /Developer
Copy contents off (essentially cp -r /Developer/* /)
Reboot
Daemon runs and patches files
Daemon deletes Trampoline
Reboot

iOSUpdater.app Notes

Placing it in iTunes and adding it to the device will allow the update.
Updater can't be deleted on device, but can with iTunes.
Requires elevated (root) privileges (as far as I can tell)
Update doesn't work if app is installed with iTunes and removed after (with iTunes).
Update does work if app is installed with iTunes and started via the app.
Deleted on successful update to 6.0.1 (10A525) or 6.0.2 (10A551)
Among with iOSUpdaterHelper.dmg, in iOSUpdater.app, there is its signature. This prevents hackers from replacing it with an unofficial image.