That's determined by the firmware and the manufacturer.
Flash isn't like disks. You don't write to a block that's on a certain cylinder on a certain platter. You write a block and the memory controller determines where it will be stored, usually based on some wear leveling algorithm.
It's one of the reasons you can't securely delete a flash drive.
Handwaving about how flash is different than disks isn't an answer to how shrinkage is conveyed to the filesystem (and isn't a meaningful differentiator anyway, since common spinny-disks haven't been 1:1 mappings for well over 3 decades, themselves).
Flash isn't like disks. You don't write to a block that's on a certain cylinder on a certain platter. You write a block and the memory controller determines where it will be stored, usually based on some wear leveling algorithm.
It's one of the reasons you can't securely delete a flash drive.