Examine source code of Keepa - Price Tracker

{
  "manifest_version": 2,
  "name": "Keepa - Amazon Price Tracker",
  "version": "1.0",
  "description": "Quick access to Keepa price tracking for Amazon products.",
  "icons": {
    "48": "icon.png"
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": "icon.png"
  },
  "permissions": [
    "activeTab"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{9a2177cd-a3bb-4df5-adaf-7b2130ec2558}"
    }
  }
}