protected function setDefaultOptions(): array
    {
        // A limit of "0" means no-limit.
        $default = [
            'limit' => 0,
            'type' => ['image', 'application']
        ];

        if (function_exists('_x')) {
            $default['l10n'] = [
                'add' => _x('Add Media', 'field', Application::TEXTDOMAIN),
                'button' => _x('Insert', 'field', Application::TEXTDOMAIN),
                'remove' => _x('Remove Selected', 'field', Application::TEXTDOMAIN),
                'title' => _x('Insert Multiple Media', 'field', Application::TEXTDOMAIN)
            ];
        }

        return array_merge($this->defaultOptions, $default);
    }