Should I override PHP DateTime with DateTimeZone after this explicitly?

I get the time:

0001-01-01T00:00:00.000Z
Greenwich Mean Time

I save this in a DateTime as:

$event->startTime = new DateTime($item->startTime, new DateTimeZone('GMT'));

What gives me:

  protected 'startTime' => 
    object(DateTime)[137]
      public 'date' => string '0001-01-01 00:00:00' (length=19)
      public 'timezone_type' => int 2
      public 'timezone' => string 'Z' (length=1)

This means that it ignores the time zone. From the docs:

Note:

The $ timezone parameter and the current time zone are ignored when the $ time parameter is a UNIX timestamp (for example, @ 946684800) or indicates a time zone (for example, 2010-01-28T15: 00: 00 + 02 :. 00)

If I then redefine it:

$event->startTime->setTimezone(new DateTimeZone('GMT'));

I get:

  protected 'startTime' => 
    object(DateTime)[137]
      public 'date' => string '0001-01-01 00:00:00' (length=19)
      public 'timezone_type' => int 3
      public 'timezone' => string 'UTC' (length=3)

So the answer says that the time zone should be GMT / UCT, which is +0, but PHP solves tl; dr , and I get my php.ini timezone by default +2. Is that not so?

, , . : UCT? , DateTime:: diff?