"Expected data source not listed"

How do I progress this issue? I wish to display a “Statistic Graph” card but at the bottom of the list of avalable Entities to add, I read this " Expected data source not listed". And, of course, it is not listed!
The entity, in my case, is called:
sensor.xy_md02_temp
… and is from an ESPHome device:

esphome:
  name: esp8266-xy-md02

esp8266:
  #board: d1_mini_pro #This is the actual board. But sometimes the OTA will fail?
  board: esp01_1m     #The compiler "says" that this will always work!

# Enable logging
logger:
  baud_rate: 0
  level: VERY_VERBOSE

# Enable Home Assistant API
api:
ota:
  password: !secret ota_password
wifi:
  ssid: !secret wifi_ssid
  password: !secret wifi_password
  domain: .peritonlane

uart:
  - id: hw_uart
    ##Software UART use GPIO0 & GPIO04
    #tx_pin: GPIO0 #marked as D3 on WiMos D1 mini pro
    #rx_pin: GPIO4 #marked as D2
    tx_pin: GPIO1 #marked as TX on WiMos D1 mini pro
    rx_pin: GPIO3 #marked as RX
    baud_rate: 9600
    stop_bits: 1
    parity: none

modbus:
  uart_id: hw_uart
  id: modbus1
  flow_control_pin: GPIO5 #marked as D1 on D1 Mini Pro
  #flow_control_pin: GPIO4 #marked as D2 on D1 Mini Pro
  
modbus_controller:
  - id: xy_md02
    address: 0x01
    modbus_id: modbus1
    
sensor:
  - platform: modbus_controller
    modbus_controller_id: xy_md02
    name: "XY-MD02 Temp"
    id: xy_md02_temp
    register_type: read
    address: 0x01
    value_type: U_WORD
    unit_of_measurement: "°C"
    accuracy_decimals: 1
    filters:
      - multiply: 0.10
  
  - platform: modbus_controller
    modbus_controller_id: xy_md02
    name: "XY-MD02 Humi"
    id: xy_md02_humi
    register_type: read
    address: 0x02
    value_type: U_WORD
    unit_of_measurement: "%"
    accuracy_decimals: 1
    filters:
      - multiply: 0.10

The “help” message says this:

You’re configuring a statistic but you couldn’t find your source in the dropdown? That’s caused by a bug in the integration providing the entity. Integrations need to configure their entities correctly so Home Assistant knows that we need to track statistics for it and how.

Open an issue with the author of the integration and link them to Sensor Entity | Home Assistant Developer Docs.

How do I track down the author? Is it the author of ESPHome Plugin, ModBus, ModBus_Controller?

Any help will be very welcome.

Regards, M.