LANGUAGE SUBTAG MODIFICATION REQUEST - zxx

[Frank Ellermann]

Karen Broome wrote:

> Hadn't even considered a use case for extending "zxx"...
> is there one?  

zxx content within a document with a different script is
an idea.  Or some variant, private use subtag, extension,
all hypothetical, and I don't see a case for a "region",
but folks will invent whatever they like best, as always.

> Agree to s/tag/subtag though.

Yes, that's shorter and clearer.

 Frank