[Dovecot] quota-warning example script from wiki2

Hi,

in the wiki there's an example script for sending an email to an user that has exceeded his quota.

Link: http://wiki2.dovecot.org/Quota/Configuration

The dovecot deliver command line is:

dovecot-lda -d $USER -o "plugin/quota=maildir:User quota:noenforcing"

I wonder about

-o: seems to be "undocumented" because I've found no information about this parameter.

If this parameter is needed what if I use dict instead of maildir? Is the syntax different?

Thanks.

-- Daniel