Bonus Map Pack
From Halopedia, the Halo wiki
The Bonus Map Pack was the first downloadable content package for Halo 2, released on April 25, 2005 alongside the Killtacular Pack. The pack was released as a free download sponsored by Mountain Dew, and was required in order to play Halo 2 Matchmaking over Xbox Live before its shutdown in 2010. The map pack was later included in the releases of the Halo 2 Multiplayer Map Pack, Halo 2 PC port and Halo: The Master Chief Collection.
Containment is a large Big Team Battle map designed for Capture the Flag and Slayer. At the time of release, Containment was one of the largest levels shipped in a Halo game.
Warlock is a small, indoor and symmetrical map and a remake of Halo: Combat Evolved's Wizard. The map is given a Forerunner theme set in the Delta Halo stome temple ruins. The map is designed to support 2-8 players, including Slayer, Oddball and Capture the Flag.