Examine source code of My Manager

{
  "manifest_version": 2,
  "name": "My Manager",
  "author": "Mukesh Bishnoi",
  "version": "1.0.0",
  "description": "Replace new tab screen with your today's Main Focus, Weather and Time.",
  "chrome_url_overrides": {
    "newtab": "index.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{a4491f42-9490-4baf-9a1f-a6f46528062f}"
    }
  }
}