How did PHP support variadic arguments before the `...$array` function argument syntax in PHP 5.6?

variadic.php

<?php

function some_old($fn) {
    // Must remove $fn to use remaining args as variadic
    $variadicArrays = array_slice(func_get_args(), 1);

    // $variadicArrays is an "implicit" argument because it's not defined in the signature
    var_dump($variadicArrays);
}

function some_new($fn, $someNewParam) {
    // Must remove $fn and now $someNewParam before variadic argument placeholder
    $variadicArrays = array_slice(func_get_args(), 2);

    // In fact, $variadicArrays is an "implicit" argument because it's not defined in the signature
    var_dump($variadicArrays);
}

$fn = function ($i) { return $i; };
some_old($fn, ['one'], ['two'], ['three']);
some_new($fn, 'Hello', ['one'], ['two'], ['three']);