"Seat positioning possibilities using sliding tracks"
The 3rd.row seat can slide all the way back until it touches the A/C cover on the left side, when sliding tracks are installed; creating increased leg room between the two rear seat rows. This 3rd. row seat will slide forward until it touches the 2nd. row seats, when increased luggage space is required.
https://www.metrisforum.com/threads/how-to-installing-euro-sliding-rails-and-euro-2-1-seats-vito.10025/#post-114645
Seats mounted on sliding tracks - Video
Tie down track,Factory track, Sliding track, Tie down fasteners.