Virtual USB (vUSB), a new addition to the Sauce Labs Real Device Cloud, allows users to conduct manual or automated testing as if there is a real device connected via a USB cable on their computer. This service simplifies the connection process and works within any network condition, without requiring additional plug-ins or modifications. vUSB also offers a range of features such as live debugging, performance monitoring, pre-build testing, and compatibility with various automation frameworks like Appium and Espresso. It provides users with line-by-line debugging capabilities, real-time log access, and the ability to test an app before packaging a new version, all without cluttering their workspace with physical devices.