And the reason that you're not just moving these into .ci/requirements-mypy.txt is in case someone wants to use a type-checking system other than mypy?

That might be reasonable, sure, I just hope that we're not going to start down the road of trying to satisfy more than one type-checking tool at the same time.

And the reason that you're not just moving these into .ci/requirements-mypy.txt is in case someone wants to use a type-checking system other than mypy?

No, it was because I wasn't sure if there was a reason for these to have been in the toxfile to begin with 😅

I can absolutely put them in requirements-mypy.txt too!

#7813 moved mypy into requirements-mypy.txt so it could be automatically updated.

I think having everything in one file sounds simplest. @hugovk ?

All in requirements-mypy.txt sounds good, that means you can also easily do stuff like:

pip install -r requirements-mypy.txt
mypy src Tests

Moved 'em all to requirements-mypy.txt.