I would like to start adding runtime support for PEP 696 . If the default parameter is added to TypeVar, ParamSpec, and TypeVarTuple, type checkers could start adding provisional support.

As I understand it, there exists a reference implementation for mypy already. It would be awesome, if we could start using that even before the PEP is formally accepted. With the 0.981 release for example, mypy added support for PEP 692 although it hasn't been approved yet.

Before I start working on it, would a PR be accepted?

/CC: @Gobot1234