I can't seem to find any information regarding pf's default behaviour
regarding broadcasts. If I have a normal NAT:ed private network and the
rule:

pass out on $ext_if from any to any keep state

What will happen with netbios broadcasts for example? pfctl -s state doesn't
list any active states to ports 137 or 139 so I suppose pf drops broadcasts
automatically but I'd really like to know if I need to explicitly block them
or if I can stop worrying...

Regards
PP