Examine source code of QuickCalc

{
  "manifest_version": 2,
  "name": "QuickCalc",
  "version": "6.1",
  "description": "Full-featured calculator in the toolbar with history and memory",
  "browser_specific_settings": {
    "gecko": {
      "id": "{c5487cd6-2584-4e0b-bb6c-b11f2249cb87}",
      "strict_min_version": "96.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "icons": {
    "16": "media/n16.png",
    "32": "media/n32.png",
    "48": "media/n48.png",
    "96": "media/n96.png",
    "128": "media/n128.png"
  },
  "browser_action": {
    "default_popup": "display/view.html",
    "default_icon": {
      "16": "media/n16.png",
      "32": "media/n32.png",
      "48": "media/n48.png",
      "96": "media/n96.png",
      "128": "media/n128.png"
    }
  },
  "background": {
    "scripts": [
      "runtime/engine.js"
    ]
  },
  "permissions": [
    "storage"
  ]
}