Code snippet:
On Python 3.9:
>>> class C(list[*a]): ...
File "<stdin>", line 1
class C(list[*a]): ...
^
SyntaxError: invalid syntax
>>>
On Python 3.10:
>>> class C(list[*a]): ...
File "<stdin>", line 1
class C(list[*a]): ...
^
SyntaxError: expected ':'
>>>
I'd have expected it to point directly at the * in both cases.