Balsa question

[Jack Ostroff <ostroffjh sbcglobal net>]

Out of curiosity, how does balsa number messages in a maildir mailbox?   
In an mbox file, they are numbered by message order within the file.  I  
mostly use mbox, but I have one maildir mailbox set up, and for some  
reason, the message numbers caught my eye, and I can't figure them  
out.  #1 is the newest message and the highest number happens to be the  
oldest, but I can't see any other pattern.

Thanks for any response or even which fine manual I should read.

Jack