config_test.module

<?php
/**
 * @file
 * Provides sample configuration files for testing.
 */

/**
 * Implements hook_config_info().
 */
function config_test_config_info() {
  $prefixes['config_test.group'] = array(
    'name_key' => 'name',
    'label_key' => 'label',
    'group' => t('Configuration test items'),
  );
  $prefixes['config_test.simple'] = array(
    'name' => t('Configuration test simple'),
    'group' => t('Configuration'),
  );
  $prefixes['config_test.dynamic.new'] = array(
    'name' => t('Dynamic config file'),
    'group' => t('Configuration'),
  );
  return $prefixes;
}

/**
 * Implements hook_config_data_validate().
 */
function config_test_config_data_validate(Config $config, ?array $config_info) {
  $fail_validation = $config->get('fail_validation');
  if ($fail_validation) {
    throw new ConfigValidateException('Configuration intentionally flagged to fail validation.');
  }
}