[Mailman-Developers] New RFC on using DKIM with MLMs

[Stephen J. Turnbull]

Joshua Cranmer writes:
 > On 10/24/2011 8:04 PM, Barry Warsaw wrote:
 > > On Oct 13, 2011, at 11:41 PM, Murray S. Kucherawy wrote:

 > >> There's movement afoot to deprecate use of "X-" in header field
 > >> names.  Just call it "Mailman-Topic".  And if it's worthwhile,
 > >> consider registering it with IANA.
 > >
 > > I wonder if we should remove the X- prefixes for Mailman 3.
 > > Here's a list of ones we still add or recognize (some might be
 > > used only in the test suite):

I would say that anything that is used only in the test suite should
still get an X-, although I suppose you could use Mailman-Test- too.

 > I believe the rule of thumb is you're supposed to use the X- prefix if 
 > it's not registered, so until the header is registered at IANA, I would 
 > vote that the X- prefix stays retained.

What Murray is saying is that the rule of thumb is changing in
response to experience.  What has happened is that the experience with
promoting an X-Foo header to just Foo has been poor, and the attendant
confusion often hinders adoption.  So many people have been in the
habit of ignoring the X- namespace anyway (the most widespread example
I know of is the adoption of Mail-Followup-To in mail, which has no[1]
sanction in the RFCs, although it's a long-standard header in news).


Footnotes: 
[1]  Last I checked, anyway, a couple years ago, but widespread usage
dates back to at least 2003.