Examine source code of Workout Timer Basic

{
  "manifest_version": 2,
  "name": "Workout Timer",
  "version": "1.0",
  "description": "This utility is called Workout Timer, which helps users track their workout time for gym exercises.",
  "permissions": [],
  "browser_action": {
    "default_popup": "game.html",
    "default_icon": {
      "128": "images/timer-logo.png"
    }
  },
  "icons": {
    "128": "images/timer-logo.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{8f6f91be-ba52-4a56-8e26-f975eee6edcd}"
    }
  }
}