I am trying to reassemble what some hack took apart. I have a 98 xj that a shop took apart multiple years ago. Since I did not take it apart I know I will have questions. I have installed an engine before so I know the basics. But I have a question that I ran into before I could start. I just want to be sure if this plug is supposed to be there. I think it is but I want to be sure.

These are pictures of what I am talking about