The Atlanta Braves are owned by Liberty Media, a publicly traded company. Because Liberty Media is publicly traded, they are required to make public financial disclosures. As a result, there is much more transparency about the Braves’ finances than there is about most other teams.
MLB currently bars teams from being owned by public companies, though the Braves (and Toronto Blue Jays, owned by Rogers Communications), were grandfathered in. Seeing the reports of the Braves’ financial success probably explains why MLB has instituted that ban, since it helps pull the curtain back on how financially successful teams are.