What exactly does CalDAV-Sync do?

Android has a bug report Add support for external calendars via iCal / CalDav that prevents you from using a standard CalDAV application. CalDAV-Sync corrects that bug: > CalDAV-Sync is a CalDAV client for Android to synchronize events. Due to its implementation as sync adapter it integrates seamlessly with the native calendar app and widgets.(Also check out CardDAV-Sync) > > Important note for Jelly Bean users: To prevent the removal of your accounts on reboot install this app: > https://play.google.com/store/apps/details?id=org.dmfs.jb.workaround.caldavsync > > This app will create new calendars on your device (one for each calendar on your server account) **How exactly does it solve it?** Is it an alternative synchronisation? Or does it correct the bug?