Reserved Mix Files
A mix file is said to be reserved when it is used by the editing community to provide some cross mod addon that any modder can utilise. These may range from patches and bug fixes to asset packs that enhance the user experience. If you are a modder who is close to releasing their mod to the world and are considering how to package it, you need to be aware of this list so you avoid conflicting with any community addon that may be used by the end user. Most reserved mix files at the moment are for Yuri's Revenge.
expandmd01.mix
This is the only additional mix file provided by EA and is provided as part of the official v1.001 patch. It contains several art assets to change the Yuri Multi-Player score screen and a selection confirm dialog box, updates to the new urban oil derrick, altered versions of several maps and updated rulesmd.ini and soundmd.ini files.
expandmd02.mix
This mix file is reserved for the mooted unofficial v1.002 patch project. It would contain art assets correcting known flaws or inconsistencies for game artwork and updated .ini files correcting other known graphical flaws and game bugs.
expandmd06.mix
This is reserved for the Terrain Expansion and contains the updated theatre.ini files that control the tiles used to construct maps. It also contains the vast number of additional tiles provided to support a wide range of additional terrain features in most of Yuri's Revenge theatres.