The Latin Extended Additional block spans U+1E00–U+1EFF, 256 codepoints in Plane 0 (Basic Multilingual Plane). Every one of them is assigned in Unicode 16.0.
All of its characters belong to the Latin script.
By general category: 132 lowercase letters (Ll), 124 uppercase letters (Lu).
The first 245 arrived in Unicode 1.1 (1993); later additions came in 2.0 (1), 5.1 (10).
245 characters here are precomposed and have canonical decompositions, so NFD splits them into a base letter plus combining marks. See normalization.