They said that the Eliminator was not a 'raid', but they also called Valigarmanda a 'raid' in that same sentence when that was previously stated to be (and pretty self-evidently) a trial, so we can therefore reason that the Eliminator isn't a trial. Or at the very least, that the Eliminator isn't the same sort of content as Valigarmanda.
My immediate read is that it's the boss of the Gamer PC Dungeon. It matches its aesthetic, after all. But I have heard another suggestion that's also fairly compelling: that it is the Gamer PC Dungeon, and we're doing a Giant of Babil thing.
