Examine source code of CurrencyCon

{
  "manifest_version": 2,
  "name": "CurrencyCon",
  "version": "1.4.4",
  "description": "Automatically converts currencies to your preferred currency",
  "icons": {
    "48": "icons/dollar-48.png"
  },
  "applications": {
    "gecko": {
      "id": "automatic-currency@anzi2001"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "*://*/*"
      ],
      "js": [
        "CurrencyCon.js"
      ]
    }
  ],
  "background": {
    "scripts": [
      "data-script.js"
    ]
  },
  "permissions": [
    "tabs",
    "menus",
    "activeTab",
    "<all_urls>",
    "storage"
  ],
  "browser_action": {
    "default_icon": "icons/dollar-48.png",
    "default_popup": "popup/choosePreferredCurrency.html"
  }
}