import type { NativeStackNavigationOptions } from '../types';
/**
 * Restores the previous header appearance on iOS 26+ for all native stack screens: an opaque
 * header that uses the theme fonts, with content below the header. Earlier iOS versions already
 * keep this appearance. Call it before the root layout renders, for example at the top level of
 * the root `_layout` file.
 *
 * > **Note:** Apple's [Human Interface Guidelines](https://developer.apple.com/design/human-interface-guidelines/toolbars)
 * > recommend that apps reduce custom navigation bar backgrounds, because they can interfere
 * > with the background effects that the system provides.
 *
 * @deprecated In a future release, the native iOS header appearance becomes the only behavior
 * and this function will be removed.
 * @platform ios
 *
 * @example
 * ```tsx app/_layout.tsx
 * import { enableLegacyHeaderAppearance, Stack } from 'expo-router';
 *
 * enableLegacyHeaderAppearance();
 *
 * export default function RootLayout() {
 *   return <Stack />;
 * }
 * ```
 */
export declare function enableLegacyHeaderAppearance(): void;
export declare function isLegacyHeaderAppearanceEnabled(): boolean;
export declare function getPlatformHeaderTransparent(headerTransparent: NativeStackNavigationOptions['headerTransparent']): boolean | undefined;