This is just a workaround app for a bug in Android 4.1 (alias Jelly Bean). See http://code.google.com/p/android/issues/detail?id=34880 for details.
Info for Samsung users: at present you'll need this app too, see http://developer.samsung.com/forum/board/thread/view.do?boardName=GeneralB&messageId=232748
Under Android 4.4.2 it's recommended to install this app as well. There is a new issue in Android that causes accounts to be removed during an app update, see http://code.google.com/p/android/issues/detail?id=66905
The bug causes accounts of paid apps to be removed when Android boots up. To work around this issue this app pretends to provide the same account type that CardDAV-Sync provides. That's enough to convince Jelly Bean to keep the account.
That's all this app does.
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 CardDAV-Sync. Please try that if you still have problems.
Please note that the bug is in Android 4.1, not in CardDAV-Sync!
If you're not using CardDAV-Sync on Jelly Bean, you don't need this app. There is no need to give it a bad rating in that case! Please don't install it in that case.