Issue #3380239 by smustgrave, pradhumanjain2311, FlusteredLondon, xjm,...

  $request_time = \Drupal::time()->getRequestTime();

  $date['short'] = [

    'name' => t("Short format"),

    'description' => t("A date in 'short' format. (%date)", ['%date' => $date_formatter->format($request_time, 'short')]),

    'description' => t("The current date in 'short' format. (%date)", ['%date' => $date_formatter->format($request_time, 'short')]),

  ];

  $date['medium'] = [

    'name' => t("Medium format"),

    'description' => t("A date in 'medium' format. (%date)", ['%date' => $date_formatter->format($request_time, 'medium')]),

    'description' => t("The current date in 'medium' format. (%date)", ['%date' => $date_formatter->format($request_time, 'medium')]),

  ];

  $date['long'] = [

    'name' => t("Long format"),

    'description' => t("A date in 'long' format. (%date)", ['%date' => $date_formatter->format($request_time, 'long')]),

    'description' => t("The current date in 'long' format. (%date)", ['%date' => $date_formatter->format($request_time, 'long')]),

  ];

  $date['custom'] = [

    'name' => t("Custom format"),

    'description' => t('A date in a custom format. See <a href="https://www.php.net/manual/datetime.format.php#refsect1-datetime.format-parameters">the PHP documentation</a> for details.'),

    'description' => t('The current date in a custom format. See <a href="https://www.php.net/manual/datetime.format.php#refsect1-datetime.format-parameters">the PHP documentation</a> for details.'),

  ];

  $date['since'] = [

    'name' => t("Time-since"),

    'description' => t("A date in 'time-since' format. (%date)", ['%date' => $date_formatter->formatTimeDiffSince($request_time - 360)]),

    'description' => t("The current date in 'time-since' format. (%date)", ['%date' => $date_formatter->formatTimeDiffSince($request_time - 360)]),

  ];

  $date['raw'] = [

    'name' => t("Raw timestamp"),

    'description' => t("A date in UNIX timestamp format (%date)", ['%date' => $request_time]),

    'description' => t("The current date in UNIX timestamp format (%date)", ['%date' => $request_time]),

  ];

  return [