lang="" vs HTTP
This test failed because it relies on :lang for results, but :lang is not supported by this browser.
If the HTTP header contains a language declaration but the html element uses an empty lang value, the UA will not recognize the language declared in the HTTP header.
This test uses :lang to detect whether the language has been set. If :lang is not supported, a message will appear and the test will fail.
Spec text: «Setting the attribute to the empty string indicates that the primary language is unknown.»