Что за последовательность? Как раскодировать?

<?php
echo uniqid();

<?php
$list = [
	'5779f6fcd2a5d',
	'577b4bcbb0bc9',
	'577ca2aadc9c7',
	'5774ca2362c64',
	'5774c7ebc9193',
	'5773764b3b753',
	'5770d7fa7b589',
	'576f6fc74158a',
];
foreach ($list as $id) {
	$timestamp = hexdec( substr($id, 0, 8) );
	echo date('Y-m-d H:i:s', $timestamp) . '<br>';
}

2016-07-04 01:41:16
2016-07-05 01:55:23
2016-07-06 02:18:18
2016-06-30 03:28:35
2016-06-30 03:19:07
2016-06-29 03:18:35
2016-06-27 03:38:34
2016-06-26 02:01:43

<?php
//$id = '5779f6fcd2a5d';
$id = uniqid();

$timestamp = hexdec( substr($id, 0, 8) );
$microtime = hexdec( substr($id, 8) );

echo '0.' . $microtime . '00 ' . $timestamp . '<br>';
echo microtime();