As referenced in Android doc for BluetootGattCharacteristic:
Represents a Bluetooth GATT Descriptor. GATT Descriptors contain additional information and attributes of a GATT characteristic, BluetoothGattCharacteristic. They can be used to describe the characteristic's features or to control certain behaviours of the characteristic.
A BluetoothGattDescriptor describes the features or to control BluetoothGattCharacteristic. But there is a method to read the BluetoothGattDescriptor from a remote device:
BluetoothGatt.readDescriptor
Reads the value for a given descriptor from the associated remote device
Why can the value of a descriptor be read from a remote device? It describes a characteristic, so I thought it should be stitched with the BluetootGattCharacteristic, isn’t it? What kind of value does it read from remote device?