[Dovecot] POP3C storage backend

I see a new "POP3C" lib-storage client backend in dovecot 2.1, but I don't see anything in the 2.1 doc directory or in the wiki. Can this be used to synchronize dovecot with external pop servers? Doing away with my current fetchmail and lmtp solution for this would be quite interesting.

Thanks for any pointers to configuring and using this, if so...