Clean Calculator Extension

manifest.json

{
  "update_url": "https://clients2.google.com/service/update2/crx",
  "manifest_version": 2,
  "name": "Clean Calculator Extension",
  "description": "A clean and simple calculator",
  "version": "1.61",
  "browser_action": {
    "default_icon": "icon128.png",
    "default_popup": "calculator.html"
  }
}