Examine source code of LyndaTimer

{
  "manifest_version": 2,
  "name": "Hello Extensions",
  "description": "Base Level Extension",
  "version": "1.0",
  "content_scripts": [
    {
      "js": [
        "scripts/content.js"
      ],
      "matches": [
        "https://developer.chrome.com/docs/extensions/*",
        "https://developer.chrome.com/docs/webstore/*",
        "https://www.linkedin.com/learning/me/*"
      ]
    }
  ],
  "permissions": [
    "tabs",
    "cookies",
    "<all_urls>"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{1057273f-827f-42a7-810d-3a67d3ef5708}"
    }
  }
}