Examine source code of TabBucket

{
  "browser_specific_settings": {
    "gecko": {
      "strict_min_version": "58.0a1",
      "id": "{e3384941-04a4-4ec1-b3a1-8ce752241117}"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "icons": {
    "32": "icons/icon32.png"
  },
  "browser_action": {
    "browser_style": true,
    "default_icon": {
      "32": "icons/icon32.png"
    },
    "default_title": "TabBucket",
    "default_popup": "tabs.html"
  },
  "description": "Save all currently open tabs for later reference.",
  "homepage_url": "https://github.com/AndrewstheBuilder/TabBucket-Firefox-Extension",
  "manifest_version": 2,
  "name": "TabBucket",
  "permissions": [
    "tabs",
    "storage"
  ],
  "version": "1.2"
}