Arthur's parametrization conjecture for the discrete spectrum of metaplectic symplectic covers

Fix a distinguished character $\overline{\chi}^0$. Let $\mathcal{A}_\epsilon(\overline{\operatorname{Sp}}_{2r}(\mathbb A))$ denote the relevant discrete-spectrum representation space, and for each Arthur parameter $\Psi$ for $\operatorname{SO}_{2r+1}$ let $\mathcal{A}_{\Psi,\overline{\chi}^0}$ be the associated near-equivalence class of genuine representations of $\overline{\operatorname{Sp}}_{2r}(\mathbb A)$. Arthur parametrization conjecture. One has

$$\mathcal{A}_\epsilon(\overline{\operatorname{Sp}}_{2r}(\mathbb A))=\hat{\bigoplus_\Psi}\mathcal{A}_{\Psi,\overline{\chi}^0}.$$

This proposes an extension of Arthur's parametrization of the discrete spectrum from linear groups to the covering group $\overline{\operatorname{Sp}}_{2r}$. The preceding discussion explains that the conjectural lifting and further development of the trace formula for covering groups may be needed to establish such a correspondence; no resolution is supplied here.