GEM - Green Engineering Menu - called like this due to its green letters on black screen look.

Originally designed bei VAG developers as a hidden menu on unit providing access to development level configuration screens and scripts.
Luckily the configuration files behind this menu - *.esd - are quite nicely human readable and can - after some try and error - be manipulated and expanded.
Based on this M.I.B offers a "user friendly" interface directly on unit.

Together with a few more discoveries this enabled us to have all these functions on our finger tips and we just need a SD card to make this possible!