Quick skim and so far I've learned that the term "black box" model is now part of exclusionary language. It's "opaque box".
Not a native speaker (never heard "clear box" as terminus technicus), but a mathematician: If it is "the (only) opposite", the relation ist symmetric. So the opposite of "clear box" is "black box" again. Skipping the injective part, "black box" would be still one possible opposite.
I would not consider the attribute "rare" to be appropriate here.
For example: I regularly deal with adversarial networks, and both black- and white-box attacks are quite common there.
Black box vs clear/open box are very well known terms. Some people use the term opaque box instead because it a more clear antonym to clear/open box.
Nonsense. This is all part of the "oppressive language" concept peddled by the neo-Marxist authoritarian types.
> Some people use the term opaque box instead because it a more clear antonym to clear/open box.
This is the first time in my life that I head the term "opaque box" used instead of "black box" in this context. I couldn't even find this phrase using a Google search.