Prediction for the moving slope of the moduli space of principally polarized abelian fivefolds

Let $\overline{\mathcal{A}}_5$ be a compactification of the moduli space of principally polarized abelian fivefolds, and let $s'(\overline{\mathcal{A}}_5)$ denote its moving slope. Since the divisor $\overline{N_0'}$ is rigid, one has $s'(\overline{\mathcal{A}}_5)>s(\overline{N_0'})$. Moving-slope prediction.

$$s'(\overline{\mathcal{A}}_5)=\frac{70}{9}.$$

This predicts the value of the moving slope and refines the preceding lower bound arising from the rigid divisor $\overline{N_0'}$; the supplied text does not state whether the prediction has been proved or remains open.