Page "Quake II" Paragraph 9

The deathmatch game benefited from the release of eight specifically designed maps that id Software added after the game's initial release.

They were introduced to the game via one of the early patches, that were released free of charge.

Prior to the release of these maps, players were limited to playing multiplayer games on the single-player levels, which, while functional as multiplayer levels, were not designed with deathmatch gameplay specifically in mind.