Examine source code of Base64Decoder

{
  "manifest_version": 2,
  "name": "Base64和JWT解码器",
  "version": "1.5",
  "description": "此扩展用于解密base64文本，在解密的同时还会进行UrlDecoder",
  "browser_action": {
    "default_icon": "img/img.png",
    "default_title": "Base64/JWT解密",
    "default_popup": "title.html"
  },
  "permissions": [
    "http://registry.novatools.vip:8081/"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{66e2bed3-691d-40a3-b516-a4f2e8c09ef0}"
    }
  }
}