Private Use High Surrogate-Dbff

Private Use High Surrogate-Dbff at U+DBFF is a non-printing surrogate code point used only as the high half of a UTF-16 surrogate pair for characters in the supplementary private-use range. It is part of the High Private Use Surrogates block and has no character meaning, glyph, or standalone text value by itself. In real data it appears inside UTF-16 text when an application encodes private-use characters above the Basic Multilingual Plane, especially from Supplementary Private Use Area-B. Such characters are used by fonts, organizations, games, archives, and specialized publishing systems to assign local symbols that Unicode has not standardized, such as custom icons, corporate marks, gaiji, or application-specific pictographs. This code point must be followed by a valid low surrogate to form one complete private-use character; alone it is ill-formed text rather than a printable symbol. The main practical gotcha is that broken copying, truncation, validation, or indexing can separate the pair, leaving U+DBFF as an orphan surrogate that may display as an error marker or be rejected by software.