:sig 0_String :see >types >string split_utf8 substr html_escape :content Primary string type used throughout UCE. `String` is an alias for `std::string`. It is used for request data, headers, cookie values, file contents, query strings, JSON text, and WebSocket payloads. Because it is backed by `std::string`, it is binary-safe and may also contain raw bytes. For UTF-8-aware splitting, use helpers such as `split_utf8()` instead of assuming one byte equals one character. :example String name = "Ada"; print(to_upper(name), "\n");