Examine source code of Last Visited Timestamp

{
  "manifest_version": 2,
  "name": "Last Visited Timestamp",
  "version": "1.0.0",
  "description": "Displays the last time the current tab was visited, helping you track your browsing history efficiently",
  "icons": {
    "48": "download-48.png"
  },
  "permissions": [
    "activeTab",
    "history"
  ],
  "browser_action": {
    "default_icon": {
      "32": "download-32.png",
      "48": "download-48.png"
    },
    "default_title": "When have i last visited?",
    "default_popup": "popup.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{88688eba-5d21-4f9c-b204-d5666fd3981a}"
    }
  }
}