Examine source code of TabTimer

{
  "manifest_version": 3,
  "name": "TabTimer",
  "version": "2.8.20",
  "description": "Smart Website Scheduler - Schedule websites to open automatically at specific times. Free forever with optional Premium features!",
  "browser_specific_settings": {
    "gecko": {
      "id": "tabtimer@aktradingpost",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ],
        "optional": []
      }
    }
  },
  "permissions": [
    "storage",
    "alarms",
    "tabs",
    "notifications",
    "contextMenus",
    "bookmarks",
    "scripting"
  ],
  "background": {
    "scripts": [
      "service_worker.js"
    ]
  },
  "action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icons/icon16.png",
      "32": "icons/icon32.png",
      "48": "icons/icon48.png",
      "128": "icons/icon128.png"
    }
  },
  "icons": {
    "16": "icons/icon16.png",
    "32": "icons/icon32.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "options_page": "options.html",
  "commands": {
    "lock-page": {
      "suggested_key": {
        "default": "Alt+L"
      },
      "description": "Lock current page"
    },
    "unlock-page": {
      "suggested_key": {
        "default": "Alt+U"
      },
      "description": "Unlock current page"
    },
    "open-options": {
      "suggested_key": {
        "default": "Alt+O"
      },
      "description": "Open management page"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "css": [
        "content.css"
      ]
    }
  ],
  "web_accessible_resources": [
    {
      "resources": [
        "welcome.html",
        "content.css"
      ],
      "matches": [
        "<all_urls>"
      ]
    }
  ]
}