# ExperimentalProtoLayoutExtensionApi

Artifact: [androidx.wear.protolayout:protolayout-expression](https://developer.android.com/jetpack/androidx/releases/wear-protolayout) [View Source](https://cs.android.com/search?q=file:androidx/wear/protolayout/expression/ExperimentalProtoLayoutExtensionApi.java+class:androidx.wear.protolayout.expression.ExperimentalProtoLayoutExtensionApi) Added in [1.0.0](https://developer.android.com/jetpack/androidx/releases/wear-protolayout#1.0.0)

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```
@RequiresOptIn(level = Level.ERROR)
@Retention(value = RetentionPolicy.CLASS)
@Target(value = [ElementType.METHOD, ElementType.TYPE, ElementType.FIELD])
public annotation ExperimentalProtoLayoutExtensionApi
```

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Denotes that this API surface is not usable by default and requires existence of an extension provider (on the rendering side).