has:

I'm only aware of one context in which this command does anything, and that's has:attachment. I'm always looking for old messages with important attachments in them, so this apparently single-purpose operator is one of my favorites. (BTW, if any of you are aware of another use for the 'has' operator, I'd love to know about it.)

filename:

If you actually know the name of the file attachment you're looking for, filename:presentation.pptx is practically indistinguishable from magic.

- (hyphen)