The MD1311 is likely referring to the MD1311 wireless network adapter, which is commonly associated with certain laptop or desktop models (like those from Acer or other manufacturers) that feature a MediaTek (formerly Ralink) Wi-Fi module. This network adapter provides wireless connectivity to the internet and local networks.
The MD1311 Windows driver is a software package that enables your Windows operating system to recognize and communicate with the MD1311 wireless network adapter. Without the correct driver, your device might not be able to connect to Wi-Fi networks.