/**
 * Resolve the entities an internal DTD subset declares and remove the subset,
 * so what reaches the XML parser is a well-formed part with no `&name;` left
 * to leak. Markup inside an entity value is escaped to text rather than
 * spliced in — an entity that opens a tag is a document we will not build.
 *
 * Text with no `<!DOCTYPE` is returned unchanged, which is every real file.
 *
 * @param xml The decoded part, as read from the package.
 * @returns The part with its internal subset resolved and stripped.
 */
export declare function resolveInternalEntities(xml: string): string;