form_mode_manager-8.x-1.x-dev/modules/examples/form_mode_manager_examples.install

<?php

/**
 * @file
 * Contains form_mode_manager_examples.install.
 */

/**
 * Implements hook_install().
 */
function form_mode_manager_examples_install() {
  // Set the front page.
  \Drupal::configFactory()
    ->getEditable('system.site')
    ->set('page.front', '/form_mode_manager_examples')
    ->save();
}