A single EFI executable containing:
- /etc/os-release file
- (optional) kernel command line
- (optional) initrd
gummiboot will enumerate /EFI/Linux/*.efi and automatically add all
files with an embedded os-release to its menu, composing the menu
entry from the data in os-release.
No bootloader configuration is needed. In EFI secure boot mode,
only a single file needs to be signed and the firmware validates
the boot loader menu entry, the initrd and the kernel command
line, because they are just part of the binary.