[lang="en-GB"], lang="en-GB-scouse"

Ignore this test. (lang= with lang attribute is not supported)
You can only get meaningful results for this test if the lang= selector works with the lang attribute, since it checks a detail with regard to that support.

Test passes if you see green below.

Text

Assertion: A lang= value with a multiple subtags will not match a lang attribute value with multiple subtags if the latter has more subtags, even if the first two subtags are the same.

Next test
HTML5

selectors-040
Result summary & related tests