A type of socket for mounting electronic devices that is designed not to stress or damage them during insertion.The guy had apparently did not know how a ZIF socket worked, and evidently didn't check the motherboard manual either as it was clearly outlined there....
Looking at the topside of the adapter, you'll notice the ZIF socket for 478 CPUs.
Flipping the motherboard over we see a metal plate situated underneath the ZIF socket.
Origin
Late 20th century: ZIF, acronym from zero insertion force.