Fedora 28 was released a few weeks ago. New Fedora 28 images are finally uploaded now.
There are no raspberry pi images any more. Just use the standard Fedora arm images, they work just fine for both arm (rpi 2) and aarch64 (rpi 3).
There efi images are for qemu. Some use grub2 as bootloader, some
use systemd-boot. The filename indicates which uses which.
The efi images can also be booted as container, using
systemd-nspawn --boot --image <file>,
but you have to convert them to raw first as systemd-nspawn can't
As usual the images don't have a root password. You have to set one using
virt-customize -a --root-password "password:<secret>",
otherwise you can't login after boot.
The images have been created with imagefish.