View Source BlueHeron.ATT.HandleValueConfirmation (blue_heron v0.5.4)
The ATT_HANDLE_VALUE_CFM PDU is sent in response to a received ATT_HANDLE_VALUE_IND PDU and confirms that the client has received an indication of the given attribute.
Bluetooth Spec v5.2, vol 3, Part F, 3.4.7.3