var_dump() looks different now

Question

This might be a stupid question, but when I print an array with var_dump() it looks different to what it looked yesterday. Looks like this:

array(2) {
  <"formular_name">=>
  string(18) "formular_userlevel"
  <"result_message_data">=>
  array(2) {
    <"positive">=>
    array(4) {
      <"message">=>
      ...
    }
  }
}

The key's names are now in <...> and I wonder why. I didn't change PHP version since yesterday.