---
title: "MTBackgroundLayer.sourceIdentifier | Mobile sdk | Mobile sdk android | Android"
description: "sourceIdentifier"
---

# MTBackgroundLayer.sourceIdentifier

@Transient

open override var [sourceIdentifier](https://docs.maptiler.com/mobile-sdk/android/api/-map-tiler-s-d-k/com.maptiler.maptilersdk.map.style.layer.background/-m-t-background-layer/source-identifier/): [String](https://kotlinlang.org/api/core/kotlin-stdlib/kotlin/-string/index.html)

Background layers do not have a source. Kept only to satisfy [MTLayer](https://docs.maptiler.com/mobile-sdk/android/api/-map-tiler-s-d-k/com.maptiler.maptilersdk.map.style.layer/-m-t-layer/) contract and excluded from serialization.