The Bopomofo Extended block spans U+31A0–U+31BF, 32 codepoints in Plane 0 (Basic Multilingual Plane). Every one of them is assigned in Unicode 16.0.
All of its characters belong to the Bopomofo script.
By general category: 32 other letters (Lo).
The first 24 arrived in Unicode 3.0 (1999); later additions came in 6.0 (3), 13.0 (5).
32 characters are East Asian Wide or Fullwidth and take two columns in terminals.