- var_dump: documentation ( source)
<?php
$diff = (new DateTimeImmutable('2021-09-01 UTC'))->diff(new DateTimeImmutable('2021-12-01 UTC'));
var_dump($diff);
$diff = (new DateTimeImmutable('2021-09-01 Asia/Tokyo'))->diff(new DateTimeImmutable('2021-12-01 Asia/Tokyo'));
var_dump($diff);