Examine source code of Design Token Extractor

{
  "manifest_version": 3,
  "name": "Design Token Extractor",
  "version": "1.0.0",
  "description": "Read any site's real design system: colour, type scale, spacing, radius and shadows. Export CSS, JSON tokens or Figma styles.",
  "permissions": [
    "activeTab",
    "scripting",
    "storage"
  ],
  "action": {
    "default_title": "Design Token Extractor — scan this page (Alt+Shift+D)",
    "default_icon": {
      "16": "icons/icon-16.png",
      "32": "icons/icon-32.png",
      "48": "icons/icon-48.png",
      "128": "icons/icon-128.png"
    }
  },
  "icons": {
    "16": "icons/icon-16.png",
    "32": "icons/icon-32.png",
    "48": "icons/icon-48.png",
    "128": "icons/icon-128.png"
  },
  "background": {
    "scripts": [
      "src/background/background.js"
    ]
  },
  "commands": {
    "toggle-panel": {
      "suggested_key": {
        "default": "Alt+Shift+D"
      },
      "description": "Scan this page for design tokens"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "design-token-extractor@balogunkrixus",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    },
    "gecko_android": {
      "strict_min_version": "142.0"
    }
  }
}