The article is primarily about how much money from various betting channels finds its way into the purse account, but I was more interested in the discussion of Tony Zhou's computer-centric approach to betting. Two things that struck me:

He does not know why his computer likes a horse, just that, at the odds, it does.

He is gleaning signal from the time at which money is bet on specific horses.

https://www.nyra.com/aqueduct/news/between-the-hedges-where-do-purses-come-from