I know Address Book metadata is stored in Library/Application Support/AddressBook.
I wonder, however, what's up with Address Book "Groups".
They are peculiar items. For example, I quit LaunchBar (it prevents deletion if it's running), then I removed all items from AddressBook, emptied trash, then started Address Book and watched Library/Application Support/AddressBook/Metadata get repopulated with the .abcdg files that define Groups.
Clearly, Address Book was getting them from somewhere! I was not logged into iCloud. I have the sense Apple doesn't like Address Book 'groups', I wonder if this is very old code.
I'm trying to find a way to clean them all out because of an iCloud Debacle related to EOL termination leading to a cascading and comical failure chain (which established, in my mind, that iCloud is a regression from MobileMe, which is saying a lot - details here -- http://tech.kateva.org/2012/06/icloud-transition-went-as-expected.html).
One aspect of the failure chain is recursive Group creation (hundreds of replicated groups).
Any advice appreciated!
Update: one guess. I think they may be coming in from somewhere in a local cache of iCloud data that's not being fully cleaned out even after logging out from iCloud.