/**
 * Recursively replaces `var` properties in a data structure with values from a `placeholders` map.
 *
 * @example
 * ```
 * const originalData = {
 *     name: 'Alice',
 *     details: { age: { var: 'AGE_PLACEHOLDER' }, city: { var: 'CITY_PLACEHOLDER' } },
 *     tags: [{ var: 'AGE_PLACEHOLDER' }, 'student']
 * };
 * const placeholders = { AGE_PLACEHOLDER: 25, CITY_PLACEHOLDER: 'New York' };
 * const newData = deepReplaceVar(originalData, placeholders); // returns { name: 'Alice', details: { age: 25, city: 'New York' }, tags: [25, 'student'] }
 * ```
 */
export declare function deepReplaceVar<T>(data: T, placeholders: Record<string, unknown>): T;