EFTXplorer

EFTXplorer (EFTX) is a tool designed to analyze, modify, decompress and convert Emergency Format Texture files (.EFT texture files) back to an easily readable and editable format (eg. bitmaps)

EM4 uses a proprietary texture compression format called ".EFT" for important / critical in-game textures. The game (and its editor modes) can convert Targa Image files (.TGA) to .EFT format, however it cannot (or simply doesn't have an option to) convert these .EFT textures back to a readable format. The biggest headache here is that you couldn't examine or alter textures unless you had access to the original .TGA file. With EFTXplorer, you can!