Message sequence/ordering when using MAILDIR format

[Curtis Generous]

What is the mailbox ordering scheme that is returned by applications
as qmail-pop3d when using MAILDIR?

For example, if when using the 'LIST' or 'UIDL' command to POP,
in what sequence will files be listed? In cronological order, or
file creation time, or ????  Do files in ~/Maildir/cur come before
~/Maildir/new? 

I wasn't able to find any mention of this either in the archives or
in any of the doc files.

Thanks

--curtis