Examine source code of Html Validator

{
  "name": "HTML Validator",
  "version": "0.9.9.5",
  "manifest_version": 2,
  "description": "Add HTML Validator in Developer Tools",
  "devtools_page": "tidy_devtools.html",
  "options_page": "common/tidy_option.html",
  "homepage_url": "http://www.gueury.com/mozilla",
  "web_accessible_resources": [
    "*"
  ],
  "background": {
    "scripts": [
      "common/tidy_platform_fake.js",
      "tidy_background.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_title": "HTML validator",
    "default_popup": "tidy_popup.html"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "tidy_content.js"
      ]
    }
  ],
  "permissions": [
    "<all_urls>",
    "storage",
    "clipboardWrite",
    "webNavigation"
  ],
  "offline_enabled": true,
  "applications": {
    "gecko": {
      "id": "{3b56bcc7-54e5-44a2-9b44-66c3ef58c13e}",
      "strict_min_version": "57.0a1"
    }
  }
}