• mkosi.version is now picked up from preset and dropin directories as
  well following the usual config precedence logic
• Removed the "first assignment wins" logic from configuration parsing.
  Settings parsed later will now override earlier values
• Removed the ! operator for lists. Instead, assign the empty string
  to the list to remove all previous values.
• Added support for configuring custom default values for settings by
  prefixing their name in the configuration file with @.
• Added QemuCdrom= to attach the image to the virtual machine as a
  CD-ROM instead of a block device.
• Added SectorSize= to set the sector size of the disk images built by
  systemd-repart.
• Added back grub support (BIOS/UEFI). Note that we don't install grub
  on UEFI yet but we do add the necessary configuration and partitions.
• Added Bootloader= option to configure which EFI bootloader to
  install. Added uki option to install just the UKI without
  systemd-boot and grub to generate grub configuration to chainload
  into the built UKIs.
• Added BiosBootloader= to configure whether grub for BIOS gets
  installed or not.
• Added QemuFirmware= to select which qemu firmware to use (OVMF,
  Seabios or direct kernel boot).
• Added QemuKernel= to specify the kernel that should be used with
  direct kernel boot.
• /var/lib/dbus/machine-id is now removed if it was added by a package
  manager postinstall script.
• The manifest is not generated by default anymore. Use
  ManifestFormat=json to make sure the manifest is generated.
• Added SourceDateEpoch= to enable more reproducible image builds.
• Added Seed= to set the seed passed to systemd-repart.
• Updated the default Fedora release to Fedora 39.
• If ToolsTree= is set to default, mkosi will now build a default
  tools tree containing all the necessary tools to build images. The
  distribution and release to use can be configured with
  ToolsTreeDistribution= and ToolsTreeRelease= or are determined
  automatically based on the image being built.
• Added uki output format. This is similar to cpio, except the cpio
  is packaged up as a UKI with a kernel image and stub picked up from
  the rootfs.