Examine source code of 遇见单词 MetWord

{
  "name": "遇见单词 MetWord",
  "description": "遇见单词是一个划词翻译扩展，标记你不认识的单词，在下次遇见时获得提醒。",
  "version": "2.2.2",
  "manifest_version": 2,
  "homepage_url": "https://metword.co",
  "icons": {
    "512": "./icons/icon.png"
  },
  "permissions": [
    "activeTab",
    "storage",
    "http://127.0.0.1/*",
    "http://localhost/*",
    "https://*.metword.co/*",
    "https://*.metnews.co/*"
  ],
  "background": {
    "scripts": [
      "./dist/background_script.js"
    ]
  },
  "browser_action": {
    "default_title": "MetWord",
    "default_icon": {
      "512": "./icons/icon.png"
    }
  },
  "content_scripts": [
    {
      "all_frames": false,
      "js": [
        "./dist/content_script.js"
      ],
      "css": [
        "./dist/content_script.css"
      ],
      "matches": [
        "*://*/*"
      ],
      "run_at": "document_idle"
    }
  ],
  "web_accessible_resources": [
    "icons/*"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{96401512-49f3-4def-be0f-f6971dfe5601}"
    }
  }
}