The loot from Super Rares scales up to Item Level 392 in Mythic Season 1.
Multiple Reddit reports suggest Blizzard has upped the Item Level of rewards from Super Rares with the start of Mythic Season 1 from Item Level 385 to 392.
Super Rares are a term coined by the community for select Rare Elites in Dragonflight, which drop loot better from the rest. You can defeat them each day for loot.
For more details about their location, check out our Super Rares Guide.