anchor.diff:  
     rootPartition = { # switch-case
       legacy = "1";
  +    "legacy+gpt" = "2";
       efi = "2";
       hybrid = "3";
     }.${partitionTableType};
  
positive.code:   format ? "raw"
  }:
  
  assert partitionTableType == "legacy" || partitionTableType == "efi" || partitionTableType == "hybrid" || partitionTableType == "none";
  # We use -E offset=X below, which is only supported by e2fsprogs
  assert partitionTableType != "none" -> fsType == "ext4";
  
  
negative.code:   #   partition of reasonable size is created in addition to the root partition.
    # For "legacy", the msdos partition table is used and a single large root
    #   partition is created.
    # For "legacy+gpt", the GPT partition table is used, a 1MiB no-fs partition for
    #   use by the bootloader is created, and a single large root partition is
    #   created.
    # For "hybrid", the GPT partition table is used and a mandatory ESP
    #   partition of reasonable size is created in addition to the root partition.
    #   Also a legacy MBR will be present.
  