wp-config in migration? | WordPress.org

I understand your interest in backing up the wp-config.php file. While it is technically possible to store wp-config.php constants in the package.json file, we have decided not to pursue this feature due to the sensitive data that the wp-config.php file contains. Storing such data in plain text can pose security risks.

If this is something that you want to include, you can manually include the file content by editing lib/model/export/class-ai1wm-export-config.php file.
You can add a new array key in line 167:

$config['Server'] = array(
    '.htaccess' => base64_encode( ai1wm_get_htaccess() ),
    'web.config' => base64_encode( ai1wm_get_webconfig() ),
    'wp-config.php' => base64_encode( file_get_contents( ABSPATH . 'wp-config.php' ) ),
);