Using the Right Tag for the Right Job - HTML5 Mastery: Semantics, Standards, and Styling - page 41

Although the preceding code snippet is handy for infuriating your XHTML-devoted
friends, it is a good idea to include the optional tags anyway, if only for clarity's sake.
While HTML5 can seem like it's bringing back coding practices from the 20th century,
it is important to remember that it is documenting what has been used in practice, not
necessarily what may be the best practice to do.
Attributes of html element
In addition to the global attributes, the html element has one new attribute, mani-
fest , which is used in a new API for creating offline applications. When you utilize