Default language (Was: Last Call: <draft-ietf-appsawg-webfinger-10.txt> (WebFinger) to Proposed Standard

[Stephane Bortzmeyer]

On Mon, Mar 04, 2013 at 12:24:30PM -0800,
 The IESG <iesg-secretary at ietf.org> wrote 
 a message of 38 lines which said:

> The IESG has received a request from the Applications Area Working Group
> WG (appsawg) to consider the following document:
> - 'WebFinger'
>   <draft-ietf-appsawg-webfinger-10.txt> as Proposed Standard

draft-ietf-appsawg-webfinger-11.txt says: 

> The "titles" object comprises zero or more name/value pairs whose
> name is a language tag or the string "default". [...] If the
> language is unknown or unspecified, then the name is "default".

Why inventing a special value when the language tag registry already
has a specific value, "und"? To quote RFC 5646:

> The 'und' (Undetermined) primary language subtag identifies
> linguistic content whose language is not determined.  This subtag
> SHOULD NOT be used unless a language tag is required and language
> information is not available or cannot be determined.

Editorial comment: the reference is wrong:

   [13]  Phillips, A., Davis, M., "Tags for Identifying Languages", RFC
         5646, January 2001.

[It is 2009]