Added compatibility YITH WooCommerce Brands Add-on Premium for brand field.

gistfile1.txt

add_filter( 'wp_schema_pro_schema_product', 'my_brand_field_mapping', 10, 3 );

/**
 * Mapping extra field for schema markup.
 *
 * @param  array $schema Schema array.
 * @param  array $data   Mapping fields array.
 * @return array
 */
function my_brand_field_mapping( $schema, $data, $post ) {
 
	$product_id  = get_the_id();
	$product     = wc_get_product( $product_id );
	
	$taxonomy    = 'yith_product_brand';
	$brand_names = wp_get_post_terms( $product_id, $taxonomy, array( 'fields' => 'names' ) );
	
	// Get the brand name
	// $brand_name = reset( $brand_names );
	foreach( $brand_names as $key => $brand ) {
    
if ( isset( $brand ) && ! empty( $brand ) ) {
				$schema['brand'][$key]['name']  = esc_html( wp_strip_all_tags( $brand ) );
			}
 
}
	
	return $schema;
}