email_registration-8.x-1.1/modules/email_registration_username/email_registration_username.install

<?php

/**
 * @file
 * Install functions for the Email registration username module.
 */

/**
 * Rename "obfuscation_value" and add "username_display_override_mode" config.
 */
function email_registration_username_update_9001() {
  $config = \Drupal::configFactory()->getEditable('email_registration_username.settings');
  $config->set('username_display_override_mode', 'disabled')
    ->set('username_display_custom', $config->get('obfuscation_value'))
    ->clear('obfuscation_value')
    ->save();
}

/**
 * Implements hook_install().
 */
function email_registration_username_install() {
  // Disable the "login_with_username" config, as it doesn't make sense with
  // this module:
  \Drupal::configFactory()->getEditable('email_registration.settings')->set('login_with_username', FALSE)->save();
}