Markup block - Gen<None> - 23 - (0:0,0)
    Tag block - Gen<TagHelper> - 23 - (0:0,0) - th:myth - mythTagHelper
        SelfClosing - <th:myth class="btn" />
        class - DoubleQuotes
            Markup span - Gen<Markup> - [btn] - SpanEditHandler;Accepts:Any - (16:0,16) - Tokens:1
                HtmlTokenType.Text;[btn];
