The doom3-linux-18.104.22.1684-sdk.x86.run file you have requested: Tools and Utilities / SDK / DOOM 3 SDK v1.3.1 - Linux - 10.55mb is not available. Perhaps try browsing all files for the game Doom III and upload any files you want to share or are missing. This is the only information we could locate:
Software development kit for DOOM 3, which you'll need to create mods. New release is compatible with the 1.3.1 patch.