Anne van Kesteren wrote:
I think that the HREFLANG attribute[1] should be allowed to be empty as well, just like xml:lang is allowed to be empty.
xml:lang is allowed to be empty to override a previous, inherited, xml:lang declaration without specifying a new language.
As xml:lang doesn't apply to the content of the linked resource, hreflang does not need to allow an empty value. If you don't want to or can't specify the language of the linked resource, just omit the hreflang attribute.
We might want to distinguish those two cases: not providing a language hint vs. explicitly telling the linked resource can't be "language qualified" but I'm not sure why this would be needed and what would be the difference (interop, accessibility, etc.)
However, we may need to make clearer that an xml:lang doesn't apply to the linked resource.
-- Thomas Broyer
