Examine source code of SpeeddaTest

{
  "description": "Adds browser action icon to toolbar to open a SpeedTest web page.",
  "manifest_version": 2,
  "name": "SpeedTest",
  "version": "1.0.0",
  "homepage_url": "http://www.blankenberg.eu/",
  "icons": {
    "48": "icons/speedtest-48.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_icon": "icons/speedtest-32.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{087b6734-36d4-4503-8529-d918ee54aef0}"
    }
  }
}