Examine source code of Sidebar Timer

{
  "manifest_version": 3,
  "name": "Sidebar Timer",
  "version": "1.0",
  "description": "A timer with templates, running in the sidebar.",
  "permissions": [
    "storage"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "sidebar_action": {
    "default_title": "Sidebar Timer",
    "default_panel": "sidebar.html",
    "default_icon": {
      "16": "icon-16.png"
    }
  },
  "icons": {
    "128": "icon-128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{cfd2cf07-491b-4c05-b2d2-3a87a1a437f1}"
    }
  }
}