This feature was discussed but not yet proposed. It allows a structured binding to appear as a condition
if (auto [ok, val] = f(...))
So the user can save an extra condition if the statement can test the value to-be-decomposed instead. Formally, it makes the value of the underlying object of the structured binding declaration also the value of a condition that is an initialized declaration.
Considering its logicality which is entirely evident from its trivial implementation, I think it might be acceptable to land it as an extension for now before I write the paper.