I just noticed this when the CC: field was added, but this applies to all fields. it's a waste of bytes, and reading time to include blank fields. so let's fix the mailer to stop doing it.
Easy enough to do, but it's not security so it probably won't go in 2.14. Of course, if I get an r= sooner, there really isn't any reason it can't go in.
Committed. Obviously it won't show up unitl b.m.o updates to the tip again.
Moving to Bugzilla product