‘wordpress.php’ file in root directory

I am trying to understand the origin of a ‘wordpress.php’ file that exists in the root directory of one of the wp sites that I support. I know this isn’t part of the initial build, but it may have been created by a plugin (perhaps WP-Auto-Upgrade?)

Here is the content of the file:

<?
        system("gunzip ./wordpress.tar.gz");
        system("tar xf ./wordpress.tar");
        system("rm -f ./wordpress.tar");

        $fp = fopen("./wp-config-sample.php", "r");
        $filecontent = fread($fp, filesize("./wp-config-sample.php"));
        $new_content = eregi_replace("%%DBNAME%%", $_REQUEST["db"], $fileconten$
        $new_content = eregi_replace("%%DBUSER%%", $_REQUEST["u"], $new_content$
        $new_content = eregi_replace("%%DBPASS%%", $_REQUEST["p"], $new_content$
        fclose($fp);

        $fp = fopen("./wp-config.php", "w");
        fputs($fp, $new_content);
        fclose($fp);
?>

It appears to simply take the data from wp-config-sample.php and place it into the wp-config.php file. Anyone know the story behind this?