What does this do? (PHP question)

[rrottman]

I am not new to PHP but can anybody try to explain what this code (extracted from register.php) in vB 3.0 RC2 actually does? Thanks in advance.

PHP Code:

$actiontemplates = array(
    'requestemail' => array(
        'activate_requestemail'
    ),
    'none' => array(
        'activateform'
    )
);