The kid has a natural ease to his motion that I love. Nothing contrived. I love the Sidd Finch comparison. Here's Bob Feller in a similar position. (more on that below)
However...I think he does have a slight trigger at the start of his motion. Before his front leg moves up, I think his hands move DOWN. Most pitchers have an up then down move with the hands...his is just down. I think it is slight, but there. It is a very simple move.
The Sidd Finch move is really unusual only in today's baseball world. The long reach and high leg was a natural move in the "ancient" baseball world. It was a kid throwing rocks move. A few guys you may have heard of have used a similar move.
Dizzy Dean
Warren Spahn
Juan Marichal
Robert Leroy "Satchel" Paige