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# NSSystemExtensionUsageDescription

A message that tells people why the app is trying to install a system extension bundle.

## Discussion

This key is required for all system extensions except <doc://com.apple.documentation/documentation/DriverKit> extensions. Failure to include this key results in an error at activation time. For DriverKit extensions, use [`OSBundleUsageDescription`](/documentation/BundleResources/Information-Property-List/OSBundleUsageDescription) instead.

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