+ * @global array $wp_registered_sidebars Stores the new sidebar in this array by sidebar ID.
+ *
+ * @param array|string $args {
+ * Optional. Array or string of arguments for the sidebar being registered.
+ *
+ * @type string $name The name or title of the sidebar displayed in the Widgets
+ * interface. Default 'Sidebar $instance'.
+ * @type string $id The unique identifier by which the sidebar will be called.
+ * Default 'sidebar-$instance'.
+ * @type string $description Description of the sidebar, displayed in the Widgets interface.
+ * Default empty string.
+ * @type string $class Extra CSS class to assign to the sidebar in the Widgets interface.
+ * Default empty.
+ * @type string $before_widget HTML content to prepend to each widget's HTML output when
+ * assigned to this sidebar. Default is an opening list item element.
+ * @type string $after_widget HTML content to append to each widget's HTML output when
+ * assigned to this sidebar. Default is a closing list item element.
+ * @type string $before_title HTML content to prepend to the sidebar title when displayed.
+ * Default is an opening h2 element.
+ * @type string $after_title HTML content to append to the sidebar title when displayed.
+ * Default is a closing h2 element.
+ * }
+ * @return string Sidebar ID added to $wp_registered_sidebars global.