Examine source code of Tracks Courier

{
  "name": "Tracks Courier",
  "description": "Track your Couriers from one place",
  "manifest_version": 2,
  "version": "0.0.1",
  "browser_action": {
    "default_icon": "logo.png",
    "default_popup": "popup.html",
    "default_title": "Tracks Courier"
  },
  "icons": {
    "128": "logo.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{687606b1-f3dd-41fd-be50-4119206ade75}"
    }
  }
}