drupalcampbristol/core/modules/ban/ban.module

<?php

/**
 * @file
 * Allows to ban individual IP addresses.
 */

use Drupal\Core\Routing\RouteMatchInterface;

/**
 * Implements hook_help().
 */
function ban_help($route_name, RouteMatchInterface $route_match) {
  switch ($route_name) {
    case 'help.page.ban':
      $output = '';
      $output .= '<h3>' . t('About') . '</h3>';
      $output .= '<p>' . t('The Ban module allows administrators to ban visits to their site from individual IP addresses. For more information, see the <a href=":url">online documentation for the Ban module</a>.', array(':url' => 'https://www.drupal.org/documentation/modules/ban')) . '</p>';
      $output .= '<h3>' . t('Uses') . '</h3>';
      $output .= '<dl>';
      $output .= '<dt>' . t('Banning IP addresses') . '</dt>';
      $output .= '<dd>' . t('Administrators can enter IP addresses to ban on the <a href=":bans">IP address bans</a> page.', array(':bans' => \Drupal::url('ban.admin_page'))) . '</dd>';
      $output .= '</dl>';
      return $output;

    case 'ban.admin_page':
      return '<p>' . t('IP addresses listed here are banned from your site. Banned addresses are completely forbidden from accessing the site and instead see a brief message explaining the situation.') . '</p>';
  }
}