import type { Root } from 'mdast';
/**
 * Removes the YAML frontmatter node from an AST (Root) if it exists as the first child.
 * Modifies the tree in place.
 * @param tree The Root node of the document.
 */
export declare const removeFrontmatterFromAST: (tree: Root) => void;
/**
 * Transforms `const X = ...; export default X;` into `export const X = ...;`
 * so that the content is valid MDX ESM. Modifies the tree in place.
 */
export declare const normalizeDefaultExportInTree: (tree: Root) => void;