This is something I haven't seen in documentation.
Since PHP 7.1, you can use short-hand list unpacking using square brackets, just like short-hand array declaration:
<?php
$foo = ['a', 'b', 'c'];
// short-hand array definition
[$a, $b, $c] = $foo;
echo $a; // displays "a"
// it's same like:
list($x, $y, $z) = $foo;
echo $x; // displays "a"
?>