These are the rawfiles that are required (next to iw4x.dll) to launch and play IW4x.
.iwd Files (iw4x_00, iw4x_01) are uncompressed in this repo and need to be compressed before they can be used by IW4x, simply create a .zip archive of the contents of the iw4x_00 and iw4x_01 folders and change the file extension to .iwd.