public static function getVariables()
    {
        // Suppress return by-ref
        $vars = [ 'env' => static::$env ];
        // needs to use a for loop, using `array_merge([], $GLOBALS);` left reference traces somehow
        foreach ($GLOBALS as $varName => $varValue) {
            $vars[$varName] = $varValue;
        }

        return $vars;
    }