Umm, the headers *are* folded.. In the very note that arrived from you, they were folded that way. Unless a friendly MTA on the way to me folded them for me, or unfolded them for you...
they aren't on my site, ron -- it' spossible you have an MTA that *is* folding them for you. Does it do laundry, too?
Folding them would be a good idea, IMHO.
I see the ones on the mailman-* lists as folded. I see the ones from the exim lists (again Mailman 2.0beta6) as unfolded. An MTA is playing silly games with the headers which is normally the sort of gratuitous fiddling that sendmail does... except the system that is playing games appears to be a postfix one (I expected better from Wietse).
I do agree that they *should* be folded by mailman when generated.
BTW Ron, any chance you could get rid of the gratuitous HTML multiparts. [They bugger the archives apart from anything else]