Examine source code of Focus Timer

{
  "manifest_version": 3,
  "name": "Focus Timer",
  "version": "1.0.0",
  "description": "Pomodoro focus timer. No data collection — works fully offline.",
  "browser_specific_settings": {
    "gecko": {
      "id": "focus-timer@extensions.local",
      "strict_min_version": "128.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "permissions": [
    "storage",
    "alarms",
    "notifications",
    "windows"
  ],
  "background": {
    "service_worker": "background.js",
    "scripts": [
      "background.js"
    ]
  },
  "action": {
    "default_popup": "popup.html",
    "default_title": "Focus Timer",
    "default_icon": {
      "16": "icons/icon16.png",
      "48": "icons/icon48.png",
      "128": "icons/icon128.png"
    }
  },
  "icons": {
    "16": "icons/icon16.png",
    "48": "icons/icon48.png",
    "96": "icons/icon96.png",
    "128": "icons/icon128.png"
  }
}