Examine source code of Calculatorr Dapps

{
  "manifest_version": 2,
  "name": "Calculator Dapps",
  "description": "",
  "version": "0.1",
  "icons": {
    "16": "./icons/16.png",
    "48": "./icons/48.png",
    "128": "./icons/128.png"
  },
  "browser_action": {
    "default_icon": "./icons/16.png",
    "default_popup": "popup.html",
    "default_title": "Calc"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{3cf42a7f-89f5-45be-93a5-69e0c18f81c5}"
    }
  }
}