The square form of the Delta conjecture

Let $n\geq1$, let $\mathsf{PSQ^E}(n)$ be the relevant set of square paths, and let $\delta(P)$ be the dinv reading word of $P$. Write $\mathsf{Des}(\delta(P))$ for its descent set and $Q_{\mathsf{Des}(\delta(P)),n}$ for the associated quasisymmetric function. The square Delta conjecture.

$$\Delta_{e_{n-1}}e_n=\sum_{P\in\mathsf{PSQ^E}(n)}q^{\mathsf{dinv}(P)}t^{\mathsf{area}(P)}Q_{\mathsf{Des}(\delta(P)),n}.$$

This is introduced as a square reformulation of the $\Delta_{e_{n-1}}e_n$ case of the Delta conjecture. The excerpt does not state a proof of this identity, so it remains open as a conjectural formulation.