not opening /dev/null

When I put an `h' flag on a recipe that drops mail into /dev/null,
process(_at_)qz(_dot_)little-neck(_dot_)ny(_dot_)us asked,

| Is that to save time for procmail? The idea being only delivering
| the headers is faster?

Yes.

| I think newer procmails know /dev/null and don't even bother opening it.

Newer procmails know to ignore a local lockfile on a drop to /dev/null --
that is, they know not to create /dev/null.$LOCKEXT.  I don't know whether
they recognize anything else special about /dev/null.