Ok, thanks for showing this. But I'm pretty sure it's a book line since I found 79 games with 5. cxd5, assuming the players are aware that they will regain the minor piece back. 79 games with a certain line is not a novelty. It must have very few or no occurences at all to be considered as one.
opening novelty Grunfeld
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I'm not saying this gives white a clear advantage or something, just pointing something out i haven't seen in books.
1. d4 Nf6
2.c4 g6
3.Nc3 d5
4.Bg5 Ne4
5.cxd5!? Nxg5
6.h4
Black's knight is trapped so white will regain the piece.