wuseman What made you draw the conclusion that Fedora isn't supporting Secure Boot? Or do you actively want to disable it? If so, why?
I want Secure Boot, but according to PrivSec:
One caveat with Fedora Atomic Desktops is that rpm-ostree currently has a hard dependency on grub and does not support Unified Kernel Images. The consequence of this is that unlike Fedora Workstation, it is not possible to set up a Fedora Atomic system with meaningful Secure Boot to resist physical tampering.