HTML 4.02

<!doctype html system "http://doctype.be/402">

HTML 4.01 (Transitional) target attribute on <a> and <link>
HTML 4.01 (Transitional) start attribute on <ol>
HTML 5 <time> element
XHTML role attribute
ARIA
RDFa, including xml:lang and proposed prefix attribute
Ruby
XHTML Basic 1.1 inputmode attribute (for <input> and <textarea>)
XHTML <access> element (Only inside document <head>; closing tag is required.)
XML Events 2 implements Attribute (for <script>)

It works in real browsers, today.