it is already mentioned in a note at the bottom of the page.
still, its true that it would be better if thus note moved up
at the main description.

Sorry, missed that note. I'm sure many others have and will. I still think it needs the example.

It seems to me that the proposed description might be an 
overspecification of the functionality.

According to <http://php.net/function.list>:

| list() only works on numerical arrays and assumes 
| the numerical indices start at 0.

Anything else might be regarded as depeding on the 
implementation, and might change in a future release.

What's the benefit of breaking the current functionality? I don't think it behaves in an implementation-specific way now, so it shouldn't in the future. It'd be better to show the example with array_values() as well:

<?php
$foo = array(2 => 'a', 'foo' => 'b', 0 => 'c');
$foo[1] = 'd';
var_dump($foo);
echo PHP_EOL;

list($x, $y, $z) = $foo;
var_dump($x, $y, $z);
echo PHP_EOL;

list($x, $y, $z) = array_values($foo);
var_dump($x, $y, $z);
?>

produces:

array(4) {
  [2]=>
  string(1) "a"
  ["foo"]=>
  string(1) "b"
  [0]=>
  string(1) "c"
  [1]=>
  string(1) "d"
}

string(1) "c"
string(1) "d"
string(1) "a"

string(1) "a"
string(1) "b"
string(1) "c"

This bug has been fixed in the documentation's XML sources. Since the
online and downloadable versions of the documentation need some time
to get updated, we would like to ask you to be a bit patient.

Thank you for the report, and for helping us make our documentation better.