Package: debian-installer In https://wiki.debian.org/UEFI We read
"debian-installer's support for UEFI is mostly contained in two modules. First comes the partman-efi module, and this will be loaded automatically if d-i recognises it has been booted in UEFI mode." The problem here is that on e.g., ASUS, there is a 50% chance that a user could have picked the plain JetFlash (where the d-i ISO is), or the same ISO, but with the UEFI: prefix...
(Don't worry about the highlighted line in that photo.)