[arch-releng] ArchIso bootloader

hello. since i work on #63166 https://bugs.archlinux.org/task/63166?project=6i have sum questions about archiso project. As far as I understand, two loaders are used. syslinux for bios and systemd-boot for efi. is it so? and why it is so? i modified syslinux config https://github.com/alex19EP/talkingarch/raw/accessible-upstreem/configs/rele... to add another entry with kernel cmdline options. do i need to add another file in configs/releng/efiboot/loader/entries for efi support? why are archiso-x86_64-cd.conf and archiso-x86_64-usb.conf? thanks.