In the context of EFI systems, what bcdedit's "/sysstore" option used for?

I never really got a good explanation how. From its example, it is used on the C: drive, which implies it is used on the Windows drive (with the Program Files folder, Windows folder, etc.)

But there's never really an explanation what a "system store device" really is. Is it where the BCD store is located? Is it the Windows C: Drive?

Can it be used on an EFI system partition to point to the boot files?