core/homeassistant/components/speedtestdotnet/icons.json

{
  "entity": {
    "sensor": {
      "ping": {
        "default": "mdi:speedometer"
      },
      "download": {
        "default": "mdi:speedometer"
      },
      "upload": {
        "default": "mdi:speedometer"
      }
    }
  }
}