Examine source code of HyperCalculator

{
  "name": "HyperCalculator",
  "description": "A Calculator extension by PequaSoft.",
  "version": "1.0.6",
  "manifest_version": 2,
  "permissions": [
    "storage"
  ],
  "icons": {
    "48": "icons/icon_48.png",
    "128": "icons/icon_128.png"
  },
  "browser_action": {
    "default_title": "Calculator",
    "default_popup": "popup/popup.html"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{c4ea1981-2ae4-4d7c-9b05-fe7c46f99359}"
    }
  }
}