Astra_Meta_Boxes::init_metabox()

		public function init_metabox() {

			add_action( 'add_meta_boxes', array( $this, 'setup_meta_box' ) );
			add_action( 'save_post', array( $this, 'save_meta_box' ) );

			/**
			 * Set metabox options
			 *
			 * @see https://php.net/manual/en/filter.filters.sanitize.php
			 */
			self::$meta_option = apply_filters(
				'astra_meta_box_options',
				array(
					'ast-hfb-above-header-display'  => array(
						'sanitize' => 'FILTER_DEFAULT',
					),
					'ast-main-header-display'       => array(
						'sanitize' => 'FILTER_DEFAULT',
					),
					'ast-hfb-below-header-display'  => array(
						'sanitize' => 'FILTER_DEFAULT',
					),
					'ast-hfb-mobile-header-display' => array(
						'sanitize' => 'FILTER_DEFAULT',
					),
					'footer-sml-layout'             => array(
						'sanitize' => 'FILTER_DEFAULT',
					),
					'footer-adv-display'            => array(
						'sanitize' => 'FILTER_DEFAULT',
					),
					'site-post-title'               => array(
						'sanitize' => 'FILTER_DEFAULT',
					),
					'site-sidebar-layout'           => array(
						'default'  => 'default',
						'sanitize' => 'FILTER_DEFAULT',
					),
					'site-content-layout'           => array(
						'default'  => 'default',
						'sanitize' => 'FILTER_DEFAULT',
					),
					'ast-featured-img'              => array(
						'sanitize' => 'FILTER_DEFAULT',
					),
					'ast-breadcrumbs-content'       => array(
						'sanitize' => 'FILTER_DEFAULT',
					),
				)
			);
		}