Examine source code of Simple Search Navigator

{
  "manifest_version": 2,
  "name": "Simple Search Navigator",
  "version": "1.0",
  "description": "Navigate through search engine results using keyboard shortcuts.",
  "permissions": [
    "activeTab"
  ],
  "content_scripts": [
    {
      "matches": [
        "*://www.google.com/*",
        "*://www.duckduckgo.com/*"
      ],
      "js": [
        "popup.js"
      ],
      "css": [
        "popup.css"
      ]
    }
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": "icon.png"
  },
  "icons": {
    "48": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{360b173e-484e-470c-935d-df6b0e13b878}"
    }
  }
}