Examine source code of Design Mode

{
  "manifest_version": 3,
  "name": "Design Mode",
  "version": "2.0.0",
  "description": "Visual DOM editor for browsers — edit styles, add comments, and send changes to coding agents via MCP",
  "permissions": [
    "activeTab",
    "storage",
    "scripting",
    "tabs",
    "sidePanel"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "content_security_policy": {
    "extension_pages": "script-src 'self'; object-src 'self'; base-uri 'self'"
  },
  "background": {
    "service_worker": "background.js",
    "scripts": [
      "background.js"
    ],
    "type": "module"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "side_panel": {
    "default_path": "sidepanel/index.html"
  },
  "sidebar_action": {
    "default_panel": "sidepanel/index.html",
    "default_title": "Design Mode",
    "default_icon": {
      "16": "icons/icon16.png",
      "48": "icons/icon48.png",
      "128": "icons/icon128.png"
    }
  },
  "action": {
    "default_title": "Design Mode",
    "default_icon": {
      "16": "icons/icon16.png",
      "48": "icons/icon48.png",
      "128": "icons/icon128.png"
    }
  },
  "icons": {
    "16": "icons/icon16.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "web_accessible_resources": [
    {
      "resources": [
        "icons/icon48.png"
      ],
      "matches": [
        "<all_urls>"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "sandeepbaskaran98@gmail.com",
      "strict_min_version": "121.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "commands": {
    "toggle-design-mode": {
      "suggested_key": {
        "default": "Alt+D",
        "mac": "Alt+D"
      },
      "description": "Toggle Design Mode"
    }
  }
}