Can any Freelander owner recognise this item?

I'd had a nightmare week trying to fix my car. After reading loads of posts I figured out the reason my freelander was running so roughly was because the fuel rail sensor cable had an intermittent fault on it. After limping home from work due to the lack of power I found my brand new cable had arrived. It was a green colour which differed from the original. However I fitted it and now it runs a lot better. My next project will be the RonBox and the EGR valve by-pass. However, with my new replacement cable there was also a plastic insert. I just couldn't work out what to do with it. There were no fitting instructions so I just plugged both ends in and it worked fine. If anyone could enlighten me I would be most appreciative. I have 3 pics of it in the hope that some recognises it.

I think its a blanking plug for the cable if you disconnect it but leave it in place so you dont get **** in there.