The Miscellaneous Mathematical Symbols-B block spans U+2980–U+29FF, 128 codepoints in Plane 0 (Basic Multilingual Plane). Every one of them is assigned in Unicode 16.0.
All of its characters have the script value Common: they are shared across writing systems rather than tied to one.
By general category: 100 math symbols (Sm), 14 opening brackets (Ps), 14 closing brackets (Pe).
The first 128 arrived in Unicode 3.2 (2002).