Examine source code of Water Reminder Plus

{
  "manifest_version": 2,
  "name": "Water Reminder",
  "version": "1.0",
  "description": "Reminds you to drink water and tracks your water intake",
  "icons": {
    "48": "icon.png"
  },
  "browser_action": {
    "default_icon": "icon.png",
    "default_popup": "popup.html"
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "permissions": [
    "alarms",
    "notifications",
    "storage"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{c790de4e-d830-472b-99d1-f94b37e85972}"
    }
  }
}