(16 code points)
|Assigned||5 code points|
|Unused||9 reserved code points |
|Unicode version history|
|1.0.0 (1991)||1 (+1)|
|2.1 (1998)||2 (+1)|
|3.0 (1999)||5 (+3)|
FFFE and FFFF are not unassigned in the usual sense, but guaranteed not to be Unicode characters at all. They can be used to guess a text's encoding scheme, since any text containing these is by definition not a correctly encoded Unicode text. Unicode's U+FEFF BYTE ORDER MARK character can be inserted at the beginning of a Unicode text to signal its endianness: a program reading such a text and encountering 0xFFFE would then know that it should switch the byte order for all the following characters.
Its block name in Unicode 1.0 was Special.