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# AdditionalHeaderFieldsAreSupported

A Boolean that indicates whether the app supports additional header fields in requests.

## Discussion

Set the corresponding value to `YES` to indicate that your browser uses the <doc://com.apple.documentation/documentation/AuthenticationServices/ASWebAuthenticationSessionRequest/additionalHeaderFields> property of an <doc://com.apple.documentation/documentation/AuthenticationServices/ASWebAuthenticationSessionRequest>.

> Important: If the system doesn’t find this key in the default browser app’s `Info.plist`, it sends the request to Safari instead.

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