# How to figure out kind of link and seperate / make single?

I have an old blend model which is obviously made of some base parts which are used multiple times. The used parts seem to be some kind of linked objects but i can't figure out which.

Why do i want to find out? I want to remove the bottom (green) parts here

but when i do, it removes all parts in the scene

I would like to remove this link and make all local/single.

Also tried the U > Unlink Object+Data attempt - dosen't get better. Also exported as obj file and reimported, but links persist.

Perhaps the curved arrow icon (first image red circle) could be a hint what kind of link this is (and how to unlink).