KPF, an acronym for KEX Pack File, is an alternate extension for ZIP files specifically for use with the KEX Engine or its older KEX 2 codebase, in the same vein as PK3. It is used to store resources specific to the KEX Engine, including such items as TARGA or PNG-format textures, wave-format sound effects, plain-text scripts and localization files, graphics shaders, tactile response data, and more. Most KEX Engine games have made use of this format.
Two KPF files are included with the 2020 re-release of Doom 64 on PC:
- Doom64.kpf, which includes resources specific to Doom 64 as implemented on top of the KEX Engine
- BNet.kpf, which includes resources specific to the Bethesda.net UI library contained within the game
Console versions include one additional KPF file each which override certain resources. Due to file system security on the systems in question, a jailbreak is generally necessary to access these files:
- ps4.kpf for the PlayStation 4
- switch.kpf for the Nintendo Switch
- xboxone.kpf for the Xbox One
Only store (method 0) and deflate (method 8) storage methods are supported by the KEX Engine.