Common
```kotlin
@ExperimentalMaterial3AdaptiveApi
sealed interface PaneExpansionStateKeyProvider
```
Interface that provides [PaneExpansionStateKey](/jetpack-compose/androidx.compose.material3.adaptive/adaptive-layout/interfaces/PaneExpansionStateKey) to remember and retrieve [PaneExpansionState](/jetpack-compose/androidx.compose.material3.adaptive/adaptive-layout/classes/PaneExpansionState)
with [rememberPaneExpansionState](/jetpack-compose/androidx.compose.material3.adaptive/adaptive-layout/composable-functions/rememberPaneExpansionState).
## Properties
Common
```kotlin
val paneExpansionStateKey: PaneExpansionStateKey
```
The key that represents the unique state of the provider to index [PaneExpansionState](/jetpack-compose/androidx.compose.material3.adaptive/adaptive-layout/classes/PaneExpansionState).