Extra connector near fuel rair sensor

Hi all, first post so go easy. Car is a Freelander TD4 registration date 31/12/03 so a facelift version.
I've been trying to trace an engine issue (hunting, intermittent lack of power when pulling away, drop in power at motorway speeds etc) but I'll follow this up in a different post. Anyway, I have just removed one of those aftermarket fuel rail boxes that modify the sensor signals just to eliminate it from my searching. I then noticed that I have a spare connector not being used that's quite near the fuel rail sensor. I thought that it may have actually been the sensor plug but if I use it instead of the black/green one it runs like a dog. Where is it meant to connect to? It must be nearby but I can't see a socket. As pictured it may be a bit misleading as I've pulled it up a bit to get it out of the way of the EGR pipe which would melt it.
Any help appreciated!

If its a ron box , the maf in use could could be a pierburg , that can only be used with the box , the oem maf is bosch !

Nah, it's a cheap box and to be honest I can't feel any difference with it out of the loop. Any idea what the black/orange connector is for?

Just to be clear, the extra connector is nothing to do with the aftermarket box, it seems to be part of the standard LR loom.

It's for nothing - if I recall correctly LR made a modification but left the old wiring in place. I have that one spare too. The green plug is the one that should be plugged in.

OK, that's great. Thanks!

Sij is completely right. Its a fuel rail sensor overlay to rectify an issue with loose pins in the original sensor connector. Modification was a new fuel rail sensor and overlay with modified pins in both the sensor and the connector.

It was to rectify an issue with poor idle and lack of power when pulling away.