You can easily do it yourself, if you are interested. Just create a signature ("dummy", "empty") file for all MongoDB classes, functiones, constants etc. For example:

-------------------------------------------------------
<?php
namespace MongoDB\Driver;

final class Manager {
    /**
     * PHPDoc comes here (@param, @return etc.)
     */
    final public __construct ( string $uri [, array $options [, array $driverOptions ]] ) {}

    ...
}

...
-------------------------------------------------------

Once such a file is created, feel free to attach it here.

Thanks.

I tried to prepare signature, but there is a problem with documentation - some methods have obviously wrong return types: http://php.net/manual/en/class.mongodb-driver-writeerror.php

Is signature acceptable without complete return types specification?

Well, it depends whether the signature file will be useful for you and other developers even with this mistakes and incomplete documentation - will it be? If yes, feel free to do it.

Thanks.