Hi,
In case there is no renderer, you can skip it (red trashcan icon next to the renderer info). In case you want to add a different renderer, tell me which ones you'd like to see in the renderers info, as I see there is indeed only one option at the moment.
Model previews show a bit of an inaccurate info at the moment, we have registered the bug and one of our developers will take a look at it once they have other works off their hands.
Cheers,
Eddie, CGTrader