I have logged your comment to get more information and explanation of free html. But I think, free html means broken html
For example, consider this HTML
<h1>Some heading </h1>
If you copy it to Notepad and then save it with .html extension and open in Web Browser, web browser will render it fine as if it is a proper html, but we know, it does not have html, head, body tags.
Besides, browsers can render html fine which does not have proper opening and closing tags.