Examine source code of SiteSEO Inspector

{
  "manifest_version": 2,
  "name": "SiteSEO Inspector",
  "version": "1.0.0",
  "description": "Instant on-page SEO analysis — meta, headings, images, links, schema and more.",
  "permissions": [
    "activeTab"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icons/icon16.png",
      "32": "icons/icon32.png",
      "48": "icons/icon48.png",
      "128": "icons/icon128.png"
    }
  },
  "icons": {
    "16": "icons/icon16.png",
    "32": "icons/icon32.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "data_collection_permissions": {
        "required": [
          "none"
        ],
        "optional": []
      },
      "id": "{22047f34-07a5-4354-9504-1f3281b34824}"
    }
  }
}