Examine source code of CPS Test - Check Clicks per Second

{
  "manifest_version": 2,
  "name": "CPS Test - Check Clicks per Second",
  "version": "3.1.1",
  "description": "Test your clicks per second. You can also set a new record. Share your score with your friend and challenge them to beat you.",
  "icons": {
    "16": "images/cps-16.png",
    "32": "images/cps-32.png",
    "48": "images/cps-48.png",
    "128": "images/cps-128.png"
  },
  "browser_action": {
    "default_icon": "images/cps-128.png",
    "default_popup": "index.html"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.mozilla.org/*"
      ],
      "js": [
        "background.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{75007e3d-f427-43b6-a288-0a75637fa8a2}"
    }
  }
}