Hyper Guardian

[Super]

I believe the gray parts you see is how the parts snap together. The purple Cargo Liner also had a vehicle included in the set that had a removable cargo grabber that can also be placed on the middle part in your picture. I always assumed that the various holes were to hold additional accessories that could be purchased separately but never came to market but I am just guessing on that. On another note, your 2 purple Cargo Liner cars with articulating wheel trucks have the sides included which is good to have as most used ones you see are missing those as they easily pop off and lost in toy boxes. They are also used to hold the PlaKids up.