Anyone know what this is?

maybe take it back to your school and ask the IT person to remove the enterprise enrolment, otherwise there’s no way to use dev mode with it

It seems you can get one from iFixit here. OWC Aura Pro X2 SSD Here is a guide Sostituzione SSD MacBook Air 13" versione inizio 2015

Some people still use these old MacBooks today. If you disassemble the MacBook into the main parts like the logic board and the top display assembly and sell the parts on eBay for people who still use these MacBooks you can make a little bit of money and help other people fix these laptops.