Most grammatical features are named by linguists so as to convey their function, e.g. conditional, inceptive, conative, concomitive, etc. The coinages are mostly based on Latn words of everyday meaning e.g. conative < conor to try.
In English, we have a usage like this: When were you going to eat? The meaning connotes a plan, as does When are you going to eat, but what function does putting it in the past serve? I would say it is simply the subjunctive because the eating hasn’t happened yet, it is just a plan.
It also has a whiff of elevated register to it. Or it may simply have been derived from the phrase When were you planning to eat? but then why would that be in the past or the subjunctive?
At any rate, my basic question is how you would label such a usage/function?