What year are we talking about? I think earlier Challengers had different seat tracks with release mechanisms on both the inner and outer tracks. There was a metal cable that ran under the seat between each track. When you pull the release lever to move the seat back, the cable moves a lever on the opposite track. The cable runs through that eyelet. My 68 Dart seats are this way. My 73 Challenger doesn't use a cable setup. There is only a release mechanism on the "outer" tracks.