[   9: Stephen J. Turnbull ] <2 text> 日光"日光"

It's necessary if you want to treat all parts equally.  For instance,
here you have a multipart/mixed with one text/plain part and one
message/rfc822.  If you select the parts on the second "level", you
get articles that have headers from the parent.  The last article here
has headers from the rfc822 part itself.  And so on.

Not doing it this way would raise the contents of the rfc822 part "up"
one level, above where it properly belongs.

-- 
(domestic pets only, the antidote for overdose, milk.)
  larsi@gnus.org * Lars Magne Ingebrigtsen