Forgive me if this has been already done, I don't see it - shouldn't we have a sticky here somewhere with all known tested IID Gap tool functions for Defenders and other models? It would be a constant work in progress to grow the list but it would be very useful.

It could start like this:

EUCD and MultiCAN:
EUCD (European Common Design) is a standardized set of configuration parameters originally developed by Ford (back when they owned Land Rover and Volvo). It acts as the "Master Hardware List."

The Purpose: It tells the car what physical parts are installed (e.g., "This car has a sunroof," "This car has power-folding mirrors").
The Logic: These are usually high-level settings. If you set a mirror to "Manual" in EUCD, the car assumes the motors don't exist, and it won't even look for the software to control them.

MultiCAN (Multiple Controller Area Network)
MultiCAN parameters are Land Rover-specific extensions added as vehicles became more complex. They act as the "Behavioral Settings."
The Purpose: It defines how the hardware behaves (e.g., "The mirrors exist, but should they unfold when the door opens or when the ignition starts?").
The Logic: MultiCAN settings often "fine-tune" the broad strokes set by the EUCD.

Example:

Parameter: EUCD-085 (Rear View Mirrors, Outside)

• Manual (This means no power folding motors are installed)
• Powerfolding (This means power folding motors are installed)

MultiCAN-505 (Ext Mirror Auto Fold)

• Enabled (mirror will fold when car is locked)
• Disabled (mirror will not fold when car is locked)

MultiCAN-703 (Ext Mirror Auto Unfold)

• Enabled (mirror will unfold when car is unlocked)
• Disabled (mirror will not unfold when car is unlocked)

...and so on and so forth.