- var_dump: documentation ( source)
- array_merge: documentation ( source)
<?php
$arr1 = [['item1', 'update']];
$arr2 = [['item2', 'create']];
$arr3 = [['item2', 'update']];
var_dump(array_merge($arr1, $arr2));
var_dump($arr1[] = $arr2);
var_dump(array_merge($arr2, $arr3));