[MlMt] These filters are awesome, but also confusing to me.

[Seebs]

Okay, what I want to do seems conceptually simple:

If a message comes to me with X-Spam-Flag: YES, I want to automatically 
move it to junk.

I can make a smart mailbox named Spam which holds all of these messages, 
but I can't seem to figure out an event that will do the same sort of 
thing.  I tried setting up an account.synchronize which looks for things 
with #source.path = 'My Spam Box', but of course this doesn't work 
because that's not really the source.

I haven't yet found any documentation explaining what the options for 
filters are, so I don't know what I can or can't do; for instance, I 
don't know of a way to examine a header in a mmCommand.

-s