o365-2.0.3/modules/o365_outlook_mail/o365_outlook_mail.install

<?php

/**
 * @file
 * Update and install hooks for the o365_outlook_mail module.
 */

use Drupal\Core\Datetime\Entity\DateFormat;

/**
 * Create our 2 custom time formats.
 */
function o365_outlook_mail_update_9001(&$sandbox) {
  $dateFormat = DateFormat::create([
    'id' => 'o365_outlook_mail_day',
    'label' => 'Microsoft 365 - Outlook mail day',
    'locked' => FALSE,
    'pattern' => 'D H:i',
  ]);
  $dateFormat->save();

  $dateFormat = DateFormat::create([
    'id' => 'o365_outlook_mail_date',
    'label' => 'Microsoft 365 - Outlook mail date',
    'locked' => FALSE,
    'pattern' => 'D j M',
  ]);
  $dateFormat->save();
}