Examine source code of Nepali Date

{
  "manifest_version": 2,
  "name": "Nepali Date",
  "version": "3.0.0",
  "description": "Show today's nepali date",
  "browser_action": {
    "default_title": "Nepali Date",
    "default_icon": "assets/icons/icon128.png",
    "default_popup": "assets/popup.html"
  },
  "permissions": [
    "alarms",
    "contextMenus",
    "idle"
  ],
  "icons": {
    "16": "assets/icons/0.jpg",
    "48": "assets/icons/icon48.png",
    "128": "assets/icons/icon128.png"
  },
  "background": {
    "scripts": [
      "assets/background.js"
    ],
    "persistent": false
  },
  "applications": {
    "gecko": {
      "id": "{4a11a005-21bc-4448-a8f0-c636c7c5ee87}"
    }
  }
}