This is not the ZCal app! The actual app is available here:
This is just a workaround app for a bug in Android 4.1 (alias Jelly Bean) and Android 4.4 (Kit Kat). More information about these bugs is available here: http://code.google.com/p/android/issues/detail?id=34880 and here:
Samsung Galaxy S4 users: at present you'll need this app too, see http://developer.samsung.com/forum/board/thread/view.do?boardName=GeneralB&messageId=232748
The bug removes accounts created by paid apps when the device is restarted. To work around the issue, this app provides an account of the same type as ZCal. This is enough to convince Android to keep ZCal accounts on reboot. That is all this app does.
Important: Please open the app at least once from within Google Play to "enable" the workaround. It may not work properly otherwise. On some devices you'll have to install this app before you install ZCal.
Please note that this is a Samsung / Android 4.1 issue, and not a bug in ZCal itself.
If your device is not a Samsung Galaxy S4 or running Android 4.1 (JellyBean), you don't need this app.
Kudos to Marten Gajda for providing the reference implementation for this app!