[WordPress] Conditional tag for WooCommerce German Market 2.x determining whether the current page is the second checkout page.

wgm-is-2nd-checkout.php

<?php
/**
 * Plugin: WooCommerce German Market 2.x
 * Conditional check whether current page is second checkout
 */
if ( ! function_exists( 'wgm_is_2nd_checkout' ) && ! is_admin() ) :
    /**
     * Check if page is WGM 2nd checkout
     *
     * @return bool
     */
    function wgm_is_2nd_checkout() {
    	$second_checkout_id = absint( get_option( 'woocommerce_check_page_id' ) );
    	return is_page( $second_checkout_id );
    }
    
    /* Debug output via plugin/functions.php */
    add_action( 'pre_get_posts', function ( $query ) {
    	
    	if ( $query->is_main_query() ) {
    		echo '<pre>is 2nd checkout (true/false): ';
    		var_export( wgm_is_2nd_checkout() );
    		echo '</pre>';
    	}
    
    	return $query;
    });
endif;