CSR is often called “driverless DFU” and is used only by BlueCore chips from Cambridge Silicon Radio (now owned by Qualcomm). The driverless just means that it's DFU like, and is routed over HID.
CSR is a ODM that makes most of the Bluetooth audio chips in vendor hardware. The hardware vendor can enable or disable features on the CSR microcontroller depending on licensing options (for instance echo cancellation), and there’s even a little virtual machine to do simple vendor-specific things.
All the CSR chips are updatable in-field, and most vendors issue updates to fix sound quality issues or to add support for new protocols or devices.
The daemon will decompress the cabinet archive and extract a firmware blob in DFU file format.
This plugin supports the following protocol ID:
These devices use the standard USB DeviceInstanceId values, e.g.
USB\VID_0A12&PID_1337&REV_2520USB\VID_0A12&PID_1337USB\VID_0A12