> There is a list owner at my site who wants *all* error messages to go to
> *all* the (non-quiet) list owners.  Will setting Errors-To= Owners
> accomplish this?  It turns out that most of the lists here are set to
> Errors-To= Owner -- is that a valid parameter?  If so, is it equivalent to
> Errors-To= Owners?  If not, how is it different?

Owner means the first owner.  Owners means all non-quiet owners.