Red letters visible on rendered page.
<meta name="assert" content="Columns are filled sequentially."/> Not true. Columns, by default, are filled in a balanced manner. " 7.1. ‘column-fill’ Name: column-fill Value: auto | balance Initial: balance Applies to: multicol elements " http://www.w3.org/TR/css3-multicol/#cf And this is the case for this test as column-fill is not declared.
The relevant test case has been removed from the website.