This section lists options affecting mailbox filters.
FILTER_DISCARD (1 or 2)
This option controls whether mailbox filter discard actions cause such discarded messages to go to the bitbucket channel (i.e., be immediately discarded), or cause such messages to go to the filter_discard channel (which will leave them around for a short period before discarding them). The default is FILTER_DISCARD=1, meaning that messages discarded by a mailbox filter are immediately discarded. Setting FILTER_DISCARD=2 causes discarded messages to instead be routed to the filter_discard channel; see Section 16.2.5 .MAX_FILEINTOS (integer)
This option specifies the maximum number of files that may be specified by a mailbox filter's fileinto operator.MAX_FORWARDS (integer)
This option specifies the maximum number of forwarding addresses that may be specified by a mailbox filter's forward operator.