Examine source code of Hydration Tracker+

{
  "description": "__MSG_extensionDescription__",
  "icons": {
    "256": "icons/icon.png"
  },
  "version": "2.0",
  "manifest_version": 2,
  "name": "__MSG_extensionName__",
  "permissions": [
    "alarms",
    "notifications"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "strict_min_version": "55.0a2",
      "id": "{532e5bad-01b5-4079-a25b-fc685a10c8de}"
    }
  }
}