Examine source code of Currency Lens

{
  "manifest_version": 2,
  "name": "Currency Lens",
  "version": "6.0",
  "description": "A lens for foreign shops: prices get a converted twin, and a built-in calculator handles the rest. No API keys, no tracking.",
  "browser_specific_settings": {
    "gecko": {
      "id": "{ceb8f6d1-2882-4797-be72-32478d5cd2cc}",
      "strict_min_version": "101.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "icons": {
    "32": "assets/icon-32.png",
    "48": "assets/icon-48.png",
    "64": "assets/icon-64.png",
    "96": "assets/icon-96.png",
    "128": "assets/icon-128.png"
  },
  "browser_action": {
    "default_title": "Currency Lens",
    "default_popup": "core/popup.html",
    "default_icon": {
      "32": "assets/icon-32.png",
      "48": "assets/icon-48.png",
      "64": "assets/icon-64.png",
      "96": "assets/icon-96.png",
      "128": "assets/icon-128.png"
    }
  },
  "permissions": [
    "storage",
    "activeTab",
    "https://open.er-api.com/*",
    "https://api.frankfurter.app/*"
  ]
}