The Arabic Extended-B block spans U+0870–U+089F, 48 codepoints in Plane 0 (Basic Multilingual Plane). 42 are assigned in Unicode 16.0; the other 6 are reserved for future characters.
All of its characters belong to the Arabic script.
By general category: 30 other letters (Lo), 9 non-spacing marks (Mn), 2 format characters (Cf), 1 modifier symbols (Sk).
The first 41 arrived in Unicode 14.0 (2021); later additions came in 16.0 (1).
Most letters here are written right to left. See bidirectional text.