Product template extensibility

product-template-extensibility.php

<?php
/**
 * Plugin Name: Test Plugin
 * Author: Joshua Flowers
 * Version: 0.1.0
 */

function test_plugin_modify_product_template() {
    $template_registry = Automattic\WooCommerce\Admin\Features\ProductBlockEditor\ProductTemplates\ProductTemplateRegistry::get_instance();
    $simple_template   = $template_registry->get_registered( 'simple' );
    if ( ! $simple_template ) {
        return;
    }
    $simple_template->add_field(
        array(
            'parent' => $simple_template::BASIC_DETAILS_SECTION,
            'block'  => array(
                'woocommerce/product-radio-field',
                array(
                    'title'    => __( 'Custom radio', 'text-domain' ),
                    'description' => __( 'Custom radio field description.', 'text-domain' ),
                    'property' => 'product_property',
                    'options'  => array(
                        array(
                            'label' => __( 'Option A', 'text-domain' ),
                            'value' => 'a',
                        ),
                        array(
                            'label' => __( 'Option B', 'text-domain' ),
                            'value' => 'b',
                        ),
                        array(
                            'label' => __( 'Option C', 'text-domain' ),
                            'value' => 'c',
                        ),
                    ),
                ),
            ),
        )
    );
}

add_action( 'init', 'test_plugin_modify_product_template' );