NPM 12 introduced 'mute alerts', but no way to use 'group by' to view the nodes affected by mute alerts, This short SWQL will display the nodes affected by mute alerts.
n.caption as [Device], n.DetailsURL as [_LinkFor_Device]
,'/Orion/images/StatusIcons/Small-' + StatusIcon AS [_IconFor_Device]
,n.IP_Address as [IP], n.DetailsURL as [_LinkFor_IP]
, Alerts.SuppressFrom as [Mute from], Alerts.SuppressUntil as [Mute Until]
from Orion.AlertSuppression AlertS
join Orion.nodes n on n.uri = AlertS.EntityURI