The complete list of features added by the “Plus” plugin can be found here: Plus Plugin home page

You can see these features throughout the Xtreme base interface. They appear greyed out with a ★Plus.

Some of them are featured on this demo site like:

• The Add Right and Left HTML on the menu bars.
• The Custom Widget Width layout in widget areas (Header, Footer, Sidebars…)
• The Equal Widget Weight in the widget areas.
• The Flow Color to the bottom, maintaining an equal height for sidebar and content.
• Some of the Full Width Options for Header, Content, and Footer areas in the Custom > Full Width BG page.
• Advanced HTML Insertion Areas in the Insertion Areas page.
• Shortcodes in the Shortcodes > Plus Plugin page.

You can check the “Plus” plugin documentation here: “Plus” plugin Documentation