/**
 * The one email pattern every Siteping surface validates against.
 *
 * The widget's identity modal and the HTTP handler's schema used to disagree
 * (a permissive regex on one side, an ASCII-only default on the other), so an
 * address the modal accepted — and persisted in localStorage for good — came
 * back as a 400 on every submission afterwards. One pattern, imported on both
 * sides, makes that drift impossible.
 *
 * Deliberately Unicode-aware: internationalised local parts and domains
 * (`françois@exemple.fr`, `user@münchen.de`, `user@हिंदी.भारत`) are real
 * addresses and common in the audience this widget serves. Combining marks
 * (`\p{M}`) are allowed alongside letters — scripts like Devanagari need them,
 * and NFD-composed input spells `ç` as `c` + U+0327 — except as the first
 * character of a domain label. Structure follows the usual rules — a local
 * part of 1 to 64 characters with no leading, trailing or doubled dot,
 * dot-separated domain labels of at most 63 characters that neither start nor
 * end with a hyphen, and a final label of at least two characters.
 */
export declare const EMAIL_PATTERN: RegExp;
/** Whether `value` is an email address Siteping accepts — see {@link EMAIL_PATTERN}. */
export declare function isValidEmail(value: string): boolean;