Examine source code of Internet Speed Fan

{
  "manifest_version": 2,
  "short_name": "Internet Speed Fan",
  "name": "Internet Speed Fan",
  "description": "A quick, accurate and aesthetically pleasing way to know your internet speed & status",
  "version": "1.3.1",
  "browser_action": {
    "default_popup": "index.html",
    "default_title": "Internet Speed Fan",
    "default_icon": "litelogo.png"
  },
  "icons": {
    "16": "litelogo.png",
    "48": "litelogo.png",
    "128": "litelogo.png"
  },
  "web_accessible_resources": [
    "index.html",
    "litelogo.png"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{438b97ed-7d76-49b7-a7fe-565213a005c2}"
    }
  }
}