<meta> tagThis text will be green if the rule has been applied.
<meta http-equiv="Link" content='<styles.css>; type="text/css"; rel=stylesheet' />
Though the HTML validates, Link is not a valid HTTP/1.1 header so the corresponding <meta http-equiv="Link"... /> tag isn't valid either.
None of the browsers tested supported the HTTP header version of this hack (sending the HTML file with the header Link: <http://www.example.com/styles.css>; REL=stylesheet).