VMD is made by Sierra its a file format for the Gob Engine the VMD Files are containg Animation, Audio, Video there can be played via VLC Media Player. (most of them but not from every game)
STK contains various Files that can be extracted via the scummvm-tools.
ITK contains various Files that can be extracted via the scummvm-tools.
mdo.ini have included some Debugging Switches.
mdo.dbg have included some Debugging Switches as well.
let Files are for Fonts.
UNINST.INF this is the Script for uninstalling the Games in this inf file are Information stored which File the Uninstaller needs to remove from the Hard Drive.
SCRIPT.INF this Script is for doing the Installation to say which Files need to copy and which Folders needs to be created and which Shortcuts needs to be created.
TOT (gob scripts binary format)
OBC (a new Script binary format for the Dev7 Engine)