/**
 * Extracts word-like tokens from a string.
 *
 * Recognizes letter runs (handling acronyms like `HTML` and PascalCase
 * boundaries like `XMLHttpRequest` → `XML`, `Http`, `Request`), digit runs,
 * and emoji. Separators (spaces, hyphens, underscores, punctuation) are
 * dropped. Returns an empty array when no tokens are present.
 *
 * @example
 * stringSplitWords('FooBar')          // ['Foo', 'Bar']
 * stringSplitWords('foo-bar')         // ['foo', 'bar']
 * stringSplitWords('FOO_BAR')         // ['FOO', 'BAR']
 * stringSplitWords('XMLHttpRequest')  // ['XML', 'Http', 'Request']
 * stringSplitWords('xhr2 request')    // ['xhr', '2', 'request']
 */
export declare function stringSplitWords(str: string): string[];