Examine source code of Easy Pomodoro Timer

{
  "manifest_version": 2,
  "name": "Pomodoro Timer",
  "version": "1.0",
  "description": "Custom Pomodoro with persistent timer and desktop notifications.",
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": "icon.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "permissions": [
    "notifications",
    "storage",
    "activeTab"
  ],
  "web_accessible_resources": [
    "sounds/notification.wav"
  ],
  "icons": {
    "16": "icon.png",
    "48": "icon.png",
    "128": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "chalokw3@hotmail.com",
      "strict_min_version": "58.0"
    }
  }
}