What it is
Most sports research starts by gathering: a box score from one site, a season split from another, a chart built by hand. Data for Sports starts after that step. Every supported league is loaded into the same structure, so a player in the NHL and a player in the NBA are read the same way.
That shared record matters more than any single feature. Because the chart, the summary, and the forecast are computed from identical game data, they can't contradict each other. When one of them changes, it's because the games changed.