- var_dump: documentation ( source)
<?php
$array = [];
$parent = ['itemListElement' => []];
$a =['@type' => 'ListItem', 'position' => '1', 'item' => ['name' => 'testName1']];
$b =['@type' => 'ListItem', 'position' => '2', 'item' => ['name' => 'testName2']];
$parent['itemListElement'][] = $a;
$parent['itemListElement'][] = $b;
var_dump($array);