Examine source code of Messaging over MQTT.

{
  "manifest_version": 2,
  "name": "MQTT Client",
  "version": "1.1",
  "permissions": [
    "https://cdnjs.cloudflare.com/ajax/libs/paho-mqtt/1.0.1/mqttws31.js",
    "https://ajax.googleapis.com/ajax/libs/jquery/2.1.3/jquery.min.js"
  ],
  "background": {
    "scripts": [
      "popup.js"
    ],
    "persistent": false
  },
  "icons": {
    "32": "favicon.png"
  },
  "description": "Messaging over MQTT.",
  "browser_action": {
    "default_popup": "popup.html"
  },
  "content_security_policy": "script-src 'self' 'unsafe-eval' https://cdnjs.cloudflare.com https://ajax.googleapis.com; object-src 'self'",
  "browser_specific_settings": {
    "gecko": {
      "id": "{ac4064cb-215b-4404-9a85-a34d49ff6cc2}"
    }
  }
}