Request for variant subtag fr 16th-c 17th-c RESUBMISSION

[Frank Ellermann]

CE Whitehead wrote:

> That is certainly likely to discourage the creation of macrolanguages for
> the purpose of resolving existing issues with already created language
> subtags.

Yes, intentional.  "Downgrading" a language subtag to an extlang subtag
isn't possible, all valid tags are guaranteed to be valid forever.  John
and Addison already explained why it's also syntactically impossible for
alpha-2 codes like fr.  But it's also not allowed for alpha-3 codes.

The first priority of RFC 4646 was "stability" (after the mess with CS),
and 4646bis won't change this:  Once a valid tag, always a valid tag.

At worst a registered subtag can be deprecated (an example is again CS),
but not removed / replaced.  In other words for variants this list has
one chance to get it right.

Frank