Who cares what it is? It looks good and works. It's allowed. If teams want to benefit from it, then copy it. And yes Audi has had this before with the R8, so there should be no complaints. If they 'missed' something, that's on them. If Oak Racing came up with it this season and it didn't get banned I don't think we'd see the same guys saying it's illegal
Just because teams didn't do what Toyota did doesn't mean it should be banned. That's how F1 works, and many here criticize that series for it's clamp down on innovation.