nginx conf文件：什么是＆lt;％...％＆gt;？

Question

我在nginx conf文件中看到过如下内容：

    <?php

    function wc_foo_cancel_unpaid_onhold_orders() {
        global $wpdb;

        $held_duration = get_option('woocommerce_hold_stock_minutes');

        if ( $held_duration < 1 || 'yes' !== get_option( 'woocommerce_manage_stock')) {
            return;
        }

        $unpaid_orders = wc_foo_cancel_unpaid_onhold_orders( strtotime( '-' . absint( $held_duration) . ' MINUTES'. current_time( 'timestamp')));

        if ( $unpaid_orders) {
                foreach ( $unpaid_orders as $unpaid_orders ){
                        $order = wc_get_order( $unpaid_order);

                    if ( apply_filters( 'woocommerce_cancel_unpaid_order', 'checkout' == $order->get_created_via(), $order ) ) {
                        $order ->update_status( 'cancelled', _( 'Unpaid order cancelled - time limite reached.', 'woocommerce'));
                    }
                }
        }

}

add_action( 'woocommerce_cancel_unpaid_orders', 'wc_foo_cancel_unpaid_onhold_orders');

function wc_foo_get_unpaid_onhold_orders( $date ){
    global $wpdb;

    $args = array(
    'date_modified' => '>' . ( time() - HOUR_IN_SECONDS ),
    'status' => 'on-hold',);
    $orders = wc_get_orders( $args );

    $unpaid_orders = $wpdb->get_col( $wpdb->prepare( "
    SELECT posts.id
    FROM {$wpdb->posts} AS posts
    WHERE posts.posts_type IN ('" . implode( "','", wc_get_order_types()). "')
    AND posts.post_status = 'wc-on-hold'
    AND posts.date_modified < %s
    ", date( 'Y-m-d H:i:s', absint( $date)) ) );
}

?>

<% if (registry.hasRootSsl) { %> 和<%是什么意思？从谷歌搜索中找到任何东西都很困难，因为这些是特殊字符，而不是单词或短语。