drupal/core/modules/pgsql/pgsql.module

<?php

/**
 * @file
 * The PostgreSQL module provides the connection between Drupal and a PostgreSQL database.
 */

use Drupal\Core\Routing\RouteMatchInterface;

/**
 * Implements hook_help().
 */
function pgsql_help($route_name, RouteMatchInterface $route_match) {
  switch ($route_name) {
    case 'help.page.pgsql':
      $output = '';
      $output .= '<h2>' . t('About') . '</h2>';
      $output .= '<p>' . t('The PostgreSQL module provides the connection between Drupal and a PostgreSQL database. For more information, see the <a href=":pgsql">online documentation for the PostgreSQL module</a>.', [':pgsql' => 'https://www.drupal.org/docs/core-modules-and-themes/core-modules/postgresql-module']) . '</p>';
      return $output;

  }
}