Packer-plugin-qemu, Box is of type raw, despite having chosen qcow2 format

After doing a packer build, when I check it's file format, qemu-img and virt-install both tell me that the file format is raw, despite having chosen qcow2 format. _qemu-img command right after packer build command_

$ sudo qemu-img info output/bastillebox-installer-box_qemu_archlinux-2023-05.qcow2
image: ./bastillebox-installer-box_qemu_archlinux-2023-05.qcow2
file format: raw
virtual size: 1.42 GiB (1522309120 bytes)
disk size: 1.42 GiB
Child node '/file':
    filename: ./bastillebox-installer-box_qemu_archlinux-2023-05.qcow2
    protocol type: file
    file length: 1.42 GiB (1522309120 bytes)
    disk size: 1.42 GiB

Below is my packer_template file: _my_packer_template.pkr.hcl_

packer {
  required_plugins {
    qemu = {
      version = ">= 1.0.9"
      source = "github.com/hashicorp/qemu"
    }
  }
}


variable "ssh_private_key_file" {
  type    = string
  default = "~/.ssh/id_bas"
}

variable "ssh_timeout" {
  type    = string
  default = "20m"

  validation {
      condition = can(regex("[0-9]+[smh]", var.ssh_timeout))
      error_message = "The ssh_timeout value must be a number followed by the letter s(econds), m(inutes), or h(ours)."
    }
}

variable "ssh_username" {
  description = "Unpriviledged user to create."
  type = string
  default = "bas"
}

locals {
  boot_command_qemu = [
    "",
    "curl -O http://{{  .HTTPIP }}:{{ .HTTPPort }}/${local.kickstart_script} && chmod +x ${local.kickstart_script} && ./${local.kickstart_script} {{ .HTTPPort }}",
  ]
  boot_command_virtualbox = [
    "",
    "curl -O http://{{  .HTTPIP }}:{{ .HTTPPort }}/${local.kickstart_script} && chmod +x ${local.kickstart_script} && ./${local.kickstart_script} {{ .HTTPPort }}",
  ]
  cpus              = 1
  disk_size         = "4G"
  efi_firmware_code = "/usr/share/edk2/x64/OVMF_CODE.4m.fd"
  efi_firmware_vars = "/usr/share/edk2/x64/OVMF_VARS.4m.fd"
  headless          = "false"
  iso_checksum      = "sha256:329b00c3e8cf094a28688c50a066b5ac6352731ccdff467f9fd7155e52d36cec"
  iso_url           = "https://mirror.cj2.nl/archlinux/iso/2023.05.03/archlinux-x86_64.iso "
  kickstart_script  = "initLiveVM.sh"
  machine_type      = "q35"
  memory            = 4096
  http_directory    = "srv"
  vm_name           = "bastille-installer"
  write_zeros       = "true"
}

source "qemu" "archlinux" {
  accelerator             = "kvm"
  boot_command            = local.boot_command_qemu
  boot_wait               = "1s"
  cpus                    = local.cpus
  disk_interface          = "virtio"
  disk_size               = local.disk_size
  efi_boot                = true
  efi_firmware_code       = local.efi_firmware_code
  efi_firmware_vars       = local.efi_firmware_vars
  format                  = "qcow2"
  headless                = local.headless
  http_directory          = local.http_directory
  iso_url                 = local.iso_url
  iso_checksum            = local.iso_checksum
  machine_type            = local.machine_type
  memory                  = local.memory
  net_device              = "virtio-net"
  shutdown_command        = "sudo systemctl start poweroff.timer"
  ssh_handshake_attempts  = 500
  ssh_port                = 22
  ssh_private_key_file    = var.ssh_private_key_file
  ssh_timeout             = var.ssh_timeout
  ssh_username            = var.ssh_username
  ssh_wait_timeout        = var.ssh_timeout
  vm_name                 = "${local.vm_name}.qcow2"
}

build {
  name = "bastille-installer"
  sources = ["source.qemu.archlinux"]

  provisioner "file" {
    destination = "/tmp/"
    source      = "./files"
  }

  provisioner "shell" {
    only = ["qemu.archlinux"]
    execute_command = "{{ .Vars }} sudo -E -S bash '{{ .Path }}'"
    expect_disconnect = true
    scripts           = [
    "scripts/liveVM.sh",
    "scripts/tables.sh",
    "scripts/partitions.sh",
    "scripts/base.sh",
    "scripts/bootloader.sh",
    "scripts/pacman.sh",
    "scripts/setup.sh"
    ]
  }

  provisioner "shell" {
    execute_command = "{{ .Vars }} WRITE_ZEROS=${local.write_zeros} sudo -E -S bash '{{ .Path }}'"
    script = "scripts/cleanup.sh"
  }

  post-processor "vagrant" {
    output = "output/${local.vm_name}_${source.type}_${source.name}-${formatdate("YYYY-MM", timestamp())}.qcow2"
    vagrantfile_template = "templates/vagrantfile.tpl"
  }
}

My full project below https://github.com/safenetwork-community/bastillebox-installer-box/tree/arch Why is the [packer-plugin-qemu](https://github.com/hashicorp/packer-plugin-qemu) not producing a box in the qcow2 format, despite me having configured it as such?