Examine source code of Water Reminder

{
  "manifest_version": 2,
  "name": "Water Reminder",
  "version": "1.0",
  "description": "Reminds you to drink water every 30 minutes with fun messages!",
  "permissions": [
    "notifications",
    "alarms"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_icon": "icon.png",
    "default_title": "Water Reminder"
  },
  "icons": {
    "48": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{d261d904-3340-4770-8765-515bddb5e267}"
    }
  }
}