/** Legacy Platform `em`. Hydrate old Y.js docs; collab normalizer rewrites to Milkdown `emphasis`. */
export declare const emCompatMark: import('@milkdown/utils').$MarkSchema<"em">;
/** Platform `code_inline`; preset equivalent is `inlineCode`. */
export declare const codeInlineCompatMark: import('@milkdown/utils').$MarkSchema<"code_inline">;
/** Platform `strikethrough`; GFM preset uses `strike_through`. */
export declare const strikethroughCompatMark: import('@milkdown/utils').$MarkSchema<"strikethrough">;