General Category - Surrogate

Surrogate is a special General Category value assigned to code points that are reserved exclusively for use in UTF-16 encoding, specifically the range U+D800 through U+DFFF. These code points do not represent any actual character or symbol in the Unicode standard; instead, they act as placeholders that, when paired together, form a surrogate pair to encode supplementary characters beyond the Basic Multilingual Plane. Because they are not valid standalone characters, they are never displayed or used in text processing, and their presence in a string indicates an encoding error if not properly combined. The surrogate value exists to mark these code points so that algorithms, parsers, and font renderers can recognize them as non-characters and handle them safely, preventing them from being confused with legitimate text or misinterpreted as meaningful data.