Examine source code of Course Task Tracker

{
  "manifest_version": 2,
  "name": "Course Task Tracker",
  "version": "1.0",
  "description": "Course Task Tracker is an interesting utility that allows you to add, edit and delete courses making it easy to track and check",
  "permissions": [],
  "browser_action": {
    "default_popup": "game.html",
    "default_icon": {
      "128": "images/cour-logo.png"
    }
  },
  "icons": {
    "128": "images/cour-logo.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{c1505731-c2ec-4b31-904c-e4b24b4a597c}"
    }
  }
}