Examine source code of URL Time Limiter

{
  "manifest_version": 2,
  "name": "URL Time Limiter",
  "version": "1.0",
  "description": "Limits the time you can spend on specific URLs by closing tabs after a set time.",
  "permissions": [
    "tabs",
    "storage",
    "notifications"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": "icon.png"
  },
  "icons": {
    "48": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{a5e4f449-7ecf-434e-ab8d-17dae87e7b72}"
    }
  }
}