Examine source code of HTML Validator Plus

{
  "name": "HTML Validator",
  "description": "Use an online HTML checker to check your HTML code. Use a syntax checker as an HTML error checker",
  "default_locale": "en",
  "version": "1.0.0.5",
  "manifest_version": 2,
  "devtools_page": "tidy_devtools.html",
  "options_page": "common/tidy_option.html",
  "homepage_url": "https://html-validator.tilda.ws/welcome",
  "web_accessible_resources": [
    "*"
  ],
  "background": {
    "scripts": [
      "tidy_service_worker.js"
    ]
  },
  "icons": {
    "16": "skin/default_icon16.png",
    "48": "skin/default_icon48.png",
    "128": "skin/default_icon128.png"
  },
  "browser_action": {
    "default_icon": "skin/disabled.png",
    "default_popup": "tidy_popup.html"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "tidy_content.js"
      ]
    }
  ],
  "permissions": [
    "storage",
    "activeTab",
    "clipboardWrite",
    "webNavigation",
    "scripting"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "offline_enabled": true,
  "browser_specific_settings": {
    "gecko": {
      "id": "{65425c80-3a3f-4bdd-a620-d0e257dbae1d}"
    }
  }
}