USB configurations

[manuelbl]

USB devices can support multiple configurations. Each configuration can have completely different interfaces, classes, protocols and endpoints. So in one configuration, the device might be a mass storage device, and in another configuration, it might be an input device (HID).

The host initially selects the first configuration. Software running on the host can later change the configuration. Configurations are always selected by the host. So the device itself cannot retain it when it is disconnected.

Do you know of any real-world devices making use of configurations? If so, what are they and what do they use it for?

Or is it an extinct USB feature?