The Combining Diacritical Marks Extended block spans U+1AB0–U+1AFF, 80 codepoints in Plane 0 (Basic Multilingual Plane). 31 are assigned in Unicode 16.0; the other 49 are reserved for future characters.
All of its characters belong to the Inherited script.
By general category: 30 non-spacing marks (Mn), 1 enclosing marks (Me).
The first 15 arrived in Unicode 7.0 (2014); later additions came in 13.0 (2), 14.0 (14).
Most characters here are combining marks. See combining diacritical marks.