This read-only counter is meant to track non-unicast (broadcast or multicast) packets sent from the host/sockets side toward the user stream; the source MIB's DESCRIPTION text is truncated and doesn't fully restate this, ending abruptly with '(i.e., a subnetwork-broadcast or subnetwork-multicast) address,' which appears to be a copy-paste/editing artifact rather than a deliberate difference in meaning. Based on its name and pairing with autifOutUcastPkts, it should be read as the outbound non-unicast packet counter. Admins use it to spot unexpected broadcast/multicast traffic being sent out to a stream.