(Slightly OT) Rare item I passed up: mCGA

When I worked at DuPont they disposed of an IBM "mCGA" monitor and display card among some other parts that I could take from work if I wanted them. The card came out of an IBM XT and the monitor looked pretty much like a regular IBM CGA monitor except that it had more of a green tint to the screen when powered off. In use it looked pretty much like a regular CGA monitor but that might be because I was only interested in verifying that I could view the RAM loading sequence upon boot up. I remember that a regular CGA was not compatible with the card, and that's the reason I originally set these two aside. We needed a "regular XT setup" more than we needed a funky monitor. I assumed it was for CAD work. Haven't seen once since. Anyone have info on this IBM CGA-like "mCGA" I can't remember what the m stood for.