Examine source code of SERPTrends Extended

{
  "manifest_version": 2,
  "name": "SERPTrends Extended",
  "version": "1.1",
  "description": "Track search trends, highlight ranking changes, and export history.",
  "permissions": [
    "storage",
    "tabs",
    "activeTab",
    "downloads"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.google.com/*",
        "*://*.bing.com/*",
        "*://*.yahoo.com/*"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_title": "SERPTrends Extended"
  },
  "options_ui": {
    "page": "options.html",
    "open_in_tab": true
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{55e40a5a-66ec-47b1-81d4-e60e819b7abb}"
    }
  }
}