$logo The path to the logo image, as defined in theme configuration.
$site_name The name of the site, empty when display has been disabled in theme settings.
$site_slogan The slogan of the site, empty when display has been disabled in theme settings.
$mission The text of the site mission, empty when display has been disabled in theme settings.
$search_box HTML to display the search box, empty if search has been disabled.
$primary_links An array containing primary navigation links for the site, if they have been configured.
$secondary_links An array containing secondary navigation links for the site, if they have been configured.
$left The HTML for the left sidebar.
$breadcrumb The breadcrumb trail for the current page.
$title The page title, for use in the actual HTML content.
$help Dynamic help text, mostly for admin pages.
$messages HTML for status and error messages. Should be displayed prominently.
$tabs Tabs linking to any sub-pages beneath the current page (e.g., the view and edit tabs when displaying a node).
$content The main content of the current Drupal page.
$right The HTML for the right sidebar.
$node The node template file.
$feed_icons A string of all feed icons for the current page.
$footer_message The footer message as defined in the admin settings.
$footer The footer region.