For advanced users modding the game, tools like or the IdTech4 File Unpacker are invaluable. Unlike standard zip tools, these were designed specifically to handle the directory structures of id Tech 4, allowing you to extract "entire game data preserving the correct files and folders structure" from multiple PK4s at once.
In a standard installation of the original Doom 3 , these files are named sequentially (e.g., pak000.pk4 , pak001.pk4 , pak002.pk4 , etc.) and reside inside the base directory. Why Do Players Search for Doom 3 PK4 Downloads? Doom 3 Pk4 Files Download