magento-log-events.php

<?php

final class Mage
{
    // ...
    public static function dispatchEvent($name, array $data = array())
    {
        $e = new Exception();
        Mage::log(
            $name . ': ' . implode(', ', array_keys($data)) . "\n"
                . $e->getTraceAsString(),
            null,
            'event.log',
            true
        );
        // ...
    }
    // ...
}