The Specials block spans U+FFF0–U+FFFF, 16 codepoints in Plane 0 (Basic Multilingual Plane). 5 are assigned in Unicode 16.0; the other 11 are reserved for future characters.
All of its characters have the script value Common: they are shared across writing systems rather than tied to one.
By general category: 3 format characters (Cf), 2 other symbols (So).
The first 1 arrived in Unicode 1.1 (1993); later additions came in 2.1 (1), 3.0 (3).