I assume it somehow protects the floppy drive while it's being transported? I have 2 of them, seems like something that should be able to be 3D printed.
I have a MAC SE that was upgraded with an internal hard drive after it was purchased in the late 80s. It had 2 800k drives that had yellow plastic slug discs pictured here to keep them from being used I'd guess.
I installed a SCSi2SD and mounted it on a 3D printed bracket (thank you @This Does...