Hello all, can anyone identify what this cavity with a springloaded ball and some kind of catch is for. I noticed it when i folded my seats forward and thought " hello what is this for?" Can anyone solve the problem? Thanks.

Early L322's had the option of putting the cargo net up behind front seats when rear seats were folded down.
Should be corresponding slots for the net to clip into in the roof lining just behind front seats.
If you don't have cargo net, then slots have no other use AFAIK.
Hope this helps.
Andy

Makes sense, after 4 years of ownership i am still getting to find new things out, even if they are useless.lol