Examine source code of ydwd

{
  "manifest_version": 2,
  "name": "ydwd",
  "version": "4.4.9",
  "description": "使用有道的API完成网页内查词和翻译(支持中英互译)。",
  "applications": {
    "gecko": {
      "id": "{4b8f9ad9-16f9-4bcf-9bb4-3b3a3d4c7724}"
    }
  },
  "icons": {
    "48": "icons/icon-48.png"
  },
  "permissions": [
    "contextMenus",
    "*://dict.youdao.com/*",
    "storage"
  ],
  "content_security_policy": "script-src 'self'; object-src 'self'; media-src https://dict.youdao.com",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "css": [
        "style.css",
        "spinner.css",
        "perfect-scrollbar.css"
      ],
      "run_at": "document_start"
    }
  ],
  "commands": {
    "ydwd-translate": {
      "suggested_key": {
        "default": "Alt+W"
      },
      "description": "Translate the selected word"
    }
  },
  "options_ui": {
    "page": "options.html"
  }
}