The name is real, but it appears in neither Bungie's documentation nor the developer's own. Here is where Project Sunrise came from and what it actually covers.

An all-time peak is a fixed historical event. It happened once, and it cannot change. So why do five Destiny 2 tracking sites report five different ones? We pulled the current Steam figures, traced the monthly history back to 2019, and worked out which trackers are reporting real data and which are guessing.