Examine source code of Call with Jabber

{
  "manifest_version": 2,
  "name": "__MSG_extensionName__",
  "description": "__MSG_extensionDescription__",
  "version": "12.6.2.1",
  "applications": {
    "gecko": {
      "id": "callwithjabber@cisco.com",
      "strict_min_version": "55.0"
    }
  },
  "background": {
    "scripts": [
      "index.js"
    ]
  },
  "permissions": [
    "menus",
    "tabs"
  ],
  "default_locale": "en"
}