Examine source code of CSS Viewer

{
  "manifest_version": 3,
  "name": "CSS Viewer",
  "version": "1.0.0",
  "description": "Extract CSS rules from a selected block and all nested elements.",
  "permissions": [
    "storage",
    "tabs"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "action": {
    "default_title": "CSS Viewer",
    "default_popup": "popup/popup.html",
    "default_icon": {
      "16": "icons/css-logo.svg",
      "32": "icons/css-logo.svg"
    }
  },
  "icons": {
    "48": "icons/css-logo.svg",
    "96": "icons/css-logo.svg"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content/content.js"
      ],
      "css": [
        "content/content.css"
      ],
      "run_at": "document_idle"
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "css-viewer@local",
      "strict_min_version": "142.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}