Examine source code of Tab Folder Organizer

{
  "manifest_version": 2,
  "name": "Tab Folder Organizer",
  "description": "Organize your tabs into custom folders.",
  "version": "2.0",
  "permissions": [
    "storage",
    "tabs",
    "contextMenus"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_popup": "index.html",
    "default_icon": "folder.png"
  },
  "icons": {
    "16": "folder.png",
    "32": "folder.png",
    "48": "folder.png",
    "128": "folder.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "keshavcse.ucs1536@gmail.com"
    }
  }
}