Having control over certain page elements of a theme can come in handy when we want to hide or show specific items. Most of the items listed pertain to user settings, such as user pictures in posts or comments, user verification status in comments, and the Shortcut icon.
Simply checking or unchecking an item will toggle the display of that item on or off. Also, keep in mind that toggling the Shortcut icon will disable the ability to add a shortcut icon as the visibility of that section is also disabled.
Gone are Logo, Site name, Site slogan, Main menu, and Secondary menu from the theme settings. These were present in Drupal 7, but have now been moved into blocks and block configuration.