/**
 * Returns the viewport content with `maximum-scale=1`, replacing an existing `maximum-scale`.
 */
export declare function addViewportMaximumScale(content: string): string;
/**
 * Stops iOS from zooming the page when a form field with a font size below 16px gets the focus.
 * Only applied on iOS, which still lets the user pinch to zoom: Android, which does not zoom
 * on focus but would lose the pinch zoom, is left untouched.
 * Does nothing when the page has no `<meta name="viewport">`.
 * @returns A function restoring the original viewport
 */
export declare function preventIosInputZoom(): () => void;