WP HTML5 Outliner

WP HTML5 Outliner (WPH5O) adds an HTML 5 outline plus a heading-level outline to the WordPress Toolbar.

Features

• Matches the outlines provided by the W3C Markup Validation Service. Caveat: In an HTML 5 outline, the W3C validator may hide some of the headings in an
  if any of them are empty. WPH5O will not. This difference is presentational, not structural.
• Adds an ‘Outline’ node to the Toolbar. Outlines are displayed in a dropdown box, with the option to view them in a new browser window.
• Runs only on pages or posts the user can edit. Administrators can view outlines for any page or post. Administration Screens are not outlined.