None that I know of. This was actually a subject of a recent discussion we had with the Teams folks, it seems even they have hard time figuring out where exactly the contacts are stored. We know it's in the user's mailbox, and most likely under the appdataroot, but I haven't been actually able to find them there for my account. And that's of course for users that have mailboxes enabled, for users without mailboxes there's obviously a different store...
I'll make sure to update this thread if I hear anything.
