Noncharacter Code Point

Unicode Version 18.0

Noncharacter Code Point is a permanent designation for a specific set of 66 code points in the Unicode standard, reserved for internal use by applications and never for interchange of text. These include the last two code points of each plane (U+FFFE, U+FFFF, and similar) plus a block of 32 at U+FDD0 through U+FDEF. Their purpose is to serve as sentinels or markers within a process, such as flagging missing data or distinguishing internal states, without risk of colliding with real characters. Software is explicitly prohibited from treating them as valid characters, and they must not appear in open text formats or protocols. While their exact behavior is implementation defined, they remain permanently noncharacters, meaning they will never be assigned meaning or become valid for general use. This ensures stability and predictability for developers who rely on their reserved status.

Yes
Abbr
Y
Count
0

Yes is assigned to code points that are permanently reserved for internal use and must never appear in interchange.
No
Abbr
N
Count
310341

No is the assigned value for code points that are permanently reserved for internal use and must never be interchanged.