Examine source code of VPN IP Guard

{
  "manifest_version": 2,
  "name": "VPN IP Guard",
  "version": "1.0",
  "description": "Blocks Facebook if your IP does not match your saved VPN IP. Shows real-time status in toolbar.",
  "permissions": [
    "tabs",
    "webRequest",
    "webRequestBlocking",
    "<all_urls>",
    "storage"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": true
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "48": "icon.png"
    }
  },
  "icons": {
    "48": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{90524899-a1e2-4ef3-bf94-efea3854f133}"
    }
  }
}