does the “Int['b nv 3']” mean？

[Syuao]

vertices: Int['b nv 3'],
faces: Int['b nf nvf'],
face_edges: Int['b e 2'] | None = None,

when I look the code，I find the part above difficult to understand ，and my ide report bug tooo：“表达式末尾出现意外标记Pylance”
plz tell me the meaning and the fix if guys know
I am very appreciate it！！！