---
title: extensionBadge
framework: quicklookthumbnailing
role: symbol
role_heading: Instance Property
path: quicklookthumbnailing/qlthumbnailreply/extensionbadge
---

# extensionBadge

A short string that identifies the file type that the system uses as a badge when producing an icon thumbnail.

## Declaration

```swift
var extensionBadge: String { get set }
```