Halo 5: Guardians players on the Xbox One can now download Cartographer's Gift, the latest free content update for the sci-fi shooter. It includes the long-awaited Halo 5 version of the Forge map editor, allowing anyone to create new multiplayer maps.
Aside from Forge, the Cartographer's Gift update includes the new SPNKr twin-tube rocket launch for Halo 5, along with three variants and some new armor. There is also a new Warzone map (Battle of Noctus), a new Arena map (Overgrowth) and two new Big Team Battle maps (Antifreeze and Burial Mounds). The full change log, which also shows a bunch of bug fixes and improvements, can be viewed on the official Halo website.
Source: Halo Waypoint