They basically gave him a bonus for winning the Super Bowl.

Per Mike Garafolo and Ian Rapoport:

Foles was originally set to earn $7 million this season, the second year of a two-year contract.

It’s another player-friendly move via Howie Roseman and Joe Douglas. Earlier this offseason they revised Stefen Wisniewski’s contract to reward him with $250k from a missed playing time incentive. Chris Long is also returning to the Birds, reportedly with a revised deal.

In other contract tweaks, Lane Johnson’s deal was restructured. Zach Ertz also agreed to a restructure.