Some LCD's will come with twin locking connectors. As illustrated below, the locking connector on the left of the image labeled #1, is the connector used by all laptops to connect the display cable running from motherboard to the display panel.
On the other hand, connector labeled #2, is a provision for future enhancements that computer manufacturers may offer as an add-on. This is in accordance with ISO norms. Please note that any connection to this connector is dependent on your laptop model and its configuration. Your laptop model may or may not have an optional add-on that goes to this connector. If you don't have a cable that runs to this connector, it means that you don't have an add-on requiring such a connector and that this connector can be left as is. This connector can be particularly helpful, if you wish to purchase an add-on offered by your laptop manufacturer such as a camera or other wired add-on requiring such a connector.