Examine source code of WhatsApp-Sender

{
  "name": "WhatsApp-Sender",
  "version": "1.1",
  "description": "",
  "permissions": [
    "tabs"
  ],
  "browser_action": {
    "default_popup": "src/popup.html",
    "default_icon": "src/img/icon.png"
  },
  "manifest_version": 2,
  "browser_specific_settings": {
    "gecko": {
      "id": "casioman@gmail.com"
    }
  }
}