Examine source code of Cash Counter

{
  "manifest_version": 2,
  "name": "Cash Counter",
  "version": "2.1",
  "description": "Effortlessly count your cash without complex math.",
  "icons": {
    "32": "icons/icon-32.png",
    "48": "icons/icon-48.png",
    "64": "icons/icon-64.png",
    "96": "icons/icon-96.png",
    "128": "icons/icon-128.png"
  },
  "browser_action": {
    "default_icon": "icons/icon-32.png",
    "default_title": "Cash Counter",
    "default_popup": "popup/main.html"
  },
  "options_ui": {
    "page": "options/options.html",
    "browser_style": false
  },
  "permissions": [
    "storage"
  ]
}