Updated notes for example 10 in arrays page

language/types/array.xml

@@ -534,10 +534,10 @@ var_dump($arr);
 
    <note>
     <para>
-     As mentioned above, if no key is specified, the maximum of the existing
-     <type>int</type> indices is taken, and the new key will be that maximum
-     value plus 1 (but at least 0). If no <type>int</type> indices exist yet, the key will
-     be <literal>0</literal> (zero).
+     As mentioned above, if no key is specified, PHP uses the next integer key: the
+     maximum existing integer index + <literal>1</literal>. If the array currently has no integer
+     indices, the key will be <literal>0</literal> (zero). For the historical behaviour prior to
+     <literal>PHP 8.3.0</literal> — where appending after a negative key could yield <literal>0</literal> — see Example #7.
     </para>
 
     <para>