This is interesting, especially the installation procedure (isn't that kinda insecure and out of Apple's policy?).

Data is saved on the mobile phone right?

ty

UPDATE: Can't install this on my iPhone unfortunately. Reports an error after the download is done.

It is a feature apple provides to beta test the apps but it requires registering users' udids. I have submitted it to the app store and put that there until they accept the app. Yep it doesn't work on non-jailbroken devices because their udids aren't registered.