Examine source code of Foxified

{
  "update_url": "https://clients2.google.com/service/update2/crx",
  "manifest_version": 2,
  "name": "__MSG_extName__",
  "description": "__MSG_extDescription__",
  "version": "1.2.2",
  "author": "Foxified",
  "homepage_url": "https://foxified.org",
  "default_locale": "en",
  "icons": {
    "16": "assets/img/icon-16px.png",
    "19": "assets/img/icon-19px.png",
    "38": "assets/img/icon-38px.png",
    "48": "assets/img/icon-48px.png",
    "128": "assets/img/icon-128px.png"
  },
  "background": {
    "page": "ff-background.html"
  },
  "options_ui": {
    "page": "ff-options.html",
    "open_in_tab": true
  },
  "browser_action": {
    "default_icon": "assets/img/icon-38px.png",
    "default_popup": "ff-popup.html"
  },
  "sandbox": {
    "pages": [
      "ff-sandbox.html"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "https://addons.mozilla.org/*/firefox/addon/*"
      ],
      "js": [
        "assets/js/ff-store.js"
      ],
      "run_at": "document_start"
    }
  ],
  "permissions": [
    "https://addons.cdn.mozilla.net/user-media/addons/*",
    "storage",
    "unlimitedStorage",
    "alarms"
  ],
  "optional_permissions": [
    "http://*/*",
    "https://*/*",
    "downloads",
    "downloads.open",
    "tabs"
  ],
  "externally_connectable": {
    "matches": [
      "https://foxified.org/*"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{b1da6234-8e0a-4001-87ff-e5fd0613de04}"
    }
  }
}