Sorry, that is what I meant by attribution (which is defined as the copyright and license in MIT).

>IANAL, but sublicensing can only impose additional clauses, it cannot roll back any grants or restrictions of the original license.

Yeah, so a CLA allows that to move to a "superlicense" kind of thing (still not sure if that word makes sense there), so they could rollback those grants or restrictions of the MIT license in the future, but they cannot do so for the past.

Which, I'm okay with in a lot of cases, as that is what I philosophically want from a permissive license. However I can see how many would not be.