TYPO3 Core

DateTime values are not only saved in UTC but also shown in UTC in BE.

When you fill a time field with 00:01 in BE it is visible in list view as 00:01 but in FE as 01:01.

TCA

            'config' => array(
                'type' => 'input',
                'size' => 8,
                'max' => 10,
                'eval' => 'time',
            ),

ExtBase model

    /**
     * Start time
     *
     * @var \DateTime
     */
    protected $startTime;

LocalConfiguration timezone settings

 [SYS][phpTimeZone] = 'Europe/Amsterdam'

So it looks like that date/time values are always saved and displayed in BE as UTC and not converted to local timezone.