This directory is populated at snapshot/remaster time.
Expected layout:
  arch/boot/x86_64/vmlinuz-linux
  arch/boot/x86_64/archiso.img
  arch/x86_64/airootfs.sfs
  arch/x86_64/airootfs.sfs.md5 (optional)
  arch/x86_64/airootfs.info (optional)
  arch/pkglist.x86_64.txt (optional)
