Data file used by ZDoom, an application used for running older games such as Doom, Heretic, and Hexen; saved in a compressed .ZIP format and contains graphics, sounds, maps, and other data; used as an alternative to the .WAD format for packaging game data.
Compressed game data file used by games based on the Quake III engine (id Tech 3), which was developed by id Software; may contain maps, textures, audio clips, or other data used for gameplay; can be modified to create custom game content. PK3 files are similar to .PAK game data files, but are based on a newer format. Since PK3 files are compressed using Zip compression, they can be renamed with a .ZIP file extension and extracted using a file decompression program such as Corel WinZip or PKWARE PKZIP. Quake III PK3 files should be saved in one of the following directories: quake3/q3ut3, quake3/baseq3, or quake3arena/q3ut3. NOTE: Examples of games that were developed using the id Tech 3 engine include Quake III Arena, Star Wars Jedi Knight II: Jedi Outcast, Soldier of Fortune II: Double Helix, Return to Castle Wolfenstein, and Call of Duty Classic.