Examine source code of Stress Level Checker

{
  "manifest_version": 2,
  "name": "Stress Level Checker",
  "version": "1.0",
  "description": "Self-assess your stress level daily in a new tab.",
  "chrome_url_overrides": {
    "newtab": "newtab.html"
  },
  "permissions": [
    "storage"
  ],
  "icons": {
    "48": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{a3e3e1a3-11f1-42ba-a8e7-8dca1a3f5475}"
    }
  }
}