The HTC Dream Composite ADB Interface driver is part of the software necessary for Android Debug Bridge (ADB) functionality on Windows when working with HTC Android devices, particularly the HTC Dream (the first Android smartphone). The ADB interface allows you to connect your HTC device to your computer for tasks like debugging, data transfer, and software development. It also provides the ability to run various commands on your Android device through the command-line interface, which is useful for app developers, device modding, or troubleshooting.

The Composite ADB Interface means that the driver allows for multiple functions (such as ADB, fastboot, and file transfer) to operate over the same USB connection, making it easier to interact with the device in different modes.