Just built the package and installed it, and got the same result with missing version numbers:
(4/6) Updating linux initcpios...
==> Building image from preset: /etc/mkinitcpio.d/linux66.preset: 'default'
==> Using default configuration file: '/etc/mkinitcpio.conf'
-> -k /boot/vmlinuz- -g /boot/initramfs-.img
==> Starting build: '6.6.30-2-MANJARO'
-> Running build hook: [base]
-> Running build hook: [udev]
-> Running build hook: [autodetect]
-> Running build hook: [kms]
-> Running build hook: [modconf]
-> Running build hook: [block]
==> WARNING: Possibly missing firmware for module: 'xhci_pci'
-> Running build hook: [keyboard]
-> Running build hook: [keymap]
-> Running build hook: [consolefont]
-> Running build hook: [plymouth]
-> Running build hook: [encrypt]
-> Running build hook: [openswap]
-> Running build hook: [resume]
-> Running build hook: [filesystems]
==> Generating module dependencies
==> Creating zstd-compressed initcpio image: '/boot/initramfs-.img'
-> Early uncompressed CPIO image generation successful
==> Initcpio image generation successful
==> Building image from preset: /etc/mkinitcpio.d/linux66.preset: 'fallback'
==> Using default configuration file: '/etc/mkinitcpio.conf'
-> -k /boot/vmlinuz- -g /boot/initramfs--fallback.img -S autodetect
==> Starting build: '6.6.30-2-MANJARO'
-> Running build hook: [base]
-> Running build hook: [udev]
-> Running build hook: [kms]
==> WARNING: Possibly missing firmware for module: 'ast'
-> Running build hook: [modconf]
-> Running build hook: [block]
==> WARNING: Possibly missing firmware for module: 'aic94xx'
==> WARNING: Possibly missing firmware for module: 'bfa'
==> WARNING: Possibly missing firmware for module: 'qed'
==> WARNING: Possibly missing firmware for module: 'qla1280'
==> WARNING: Possibly missing firmware for module: 'qla2xxx'
==> WARNING: Possibly missing firmware for module: 'wd719x'
==> WARNING: Possibly missing firmware for module: 'xhci_pci'
-> Running build hook: [keyboard]
-> Running build hook: [keymap]
-> Running build hook: [consolefont]
-> Running build hook: [plymouth]
-> Running build hook: [encrypt]
-> Running build hook: [openswap]
-> Running build hook: [resume]
-> Running build hook: [filesystems]
==> Generating module dependencies
==> Creating zstd-compressed initcpio image: '/boot/initramfs--fallback.img'
-> Early uncompressed CPIO image generation successful
==> Initcpio image generation successful
==> Building image from preset: /etc/mkinitcpio.d/linux68.preset: 'default'
==> Using default configuration file: '/etc/mkinitcpio.conf'
-> -k /boot/vmlinuz- -g /boot/initramfs-.img
==> Starting build: '6.6.30-2-MANJARO'
-> Running build hook: [base]
-> Running build hook: [udev]
-> Running build hook: [autodetect]
-> Running build hook: [kms]
-> Running build hook: [modconf]
-> Running build hook: [block]
==> WARNING: Possibly missing firmware for module: 'xhci_pci'
-> Running build hook: [keyboard]
-> Running build hook: [keymap]
-> Running build hook: [consolefont]
-> Running build hook: [plymouth]
-> Running build hook: [encrypt]
-> Running build hook: [openswap]
-> Running build hook: [resume]
-> Running build hook: [filesystems]
==> Generating module dependencies
==> Creating zstd-compressed initcpio image: '/boot/initramfs-.img'
-> Early uncompressed CPIO image generation successful
==> Initcpio image generation successful
==> Building image from preset: /etc/mkinitcpio.d/linux68.preset: 'fallback'
==> Using default configuration file: '/etc/mkinitcpio.conf'
-> -k /boot/vmlinuz- -g /boot/initramfs-.img -S autodetect
==> Starting build: '6.6.30-2-MANJARO'
-> Running build hook: [base]
-> Running build hook: [udev]
-> Running build hook: [kms]
==> WARNING: Possibly missing firmware for module: 'ast'
-> Running build hook: [modconf]
-> Running build hook: [block]
==> WARNING: Possibly missing firmware for module: 'aic94xx'
==> WARNING: Possibly missing firmware for module: 'bfa'
==> WARNING: Possibly missing firmware for module: 'qed'
==> WARNING: Possibly missing firmware for module: 'qla1280'
==> WARNING: Possibly missing firmware for module: 'qla2xxx'
==> WARNING: Possibly missing firmware for module: 'wd719x'
==> WARNING: Possibly missing firmware for module: 'xhci_pci'
-> Running build hook: [keyboard]
-> Running build hook: [keymap]
-> Running build hook: [consolefont]
-> Running build hook: [plymouth]
-> Running build hook: [encrypt]
-> Running build hook: [openswap]
-> Running build hook: [resume]
-> Running build hook: [filesystems]
==> Generating module dependencies
==> Creating zstd-compressed initcpio image: '/boot/initramfs-.img'
-> Early uncompressed CPIO image generation successful
==> Initcpio image generation successful
> ls /boot/
efi/ initramfs--fallback.img intel-ucode.img linux68-x86_64.kver vmlinuz-
grub/ initramfs-.img linux66-x86_64.kver memtest86+/
Or am I still missing something?
Also, this may not be helpful, but I just noticed that even when I explicitly run sudo mkinitcpio -p linux68, it’s still building the image for linux 6.6:
==> Starting build: '6.6.30-2-MANJARO'