Examine source code of Cryptalert

{
  "name": "Cryptalert",
  "version": "3.0.5resigned1",
  "description": "Receive web notifications of your alerts on cryptalert.com.",
  "browser_action": {
    "default_icon": {
      "16": "16.png"
    },
    "default_title": "Cryptalert",
    "default_popup": "index.html"
  },
  "icons": {
    "16": "16.png",
    "48": "48.png",
    "128": "128.png"
  },
  "permissions": [
    "https://cryptalert.com/*",
    "notifications"
  ],
  "background": {
    "scripts": [
      "jquery-3.2.1.min.js",
      "background.js"
    ]
  },
  "manifest_version": 2,
  "web_accessible_resources": [
    "48.png"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{25a85ba2-6a2f-4d18-8ecb-aa24933a78be}"
    }
  }
}