/**
 * Internationalization helpers for popup
 */
/**
 * Translate a key to localized string
 * @param key - Translation key
 * @param substitutions - Optional substitutions
 * @returns Translated string
 */
export declare const translate: (key: string, substitutions?: string | string[]) => string;
/**
 * Get the current UI locale
 * @returns Locale code (e.g., 'en', 'zh-CN')
 */
export declare const getUiLocale: () => string;
/**
 * Apply internationalized text to DOM elements
 * Elements with data-i18n attribute will have their text content replaced
 * Elements with data-i18n-attr attribute will have specified attributes set
 */
export declare const applyI18nText: () => void;