/etc/grub/10_linux_zfs has bad zpool command

$ lsb_release -rd
No LSB modules are available.
Description: Ubuntu 23.04
Release: 23.04

$ apt-cache policy grub-common
grub-common:
  Installed: 2.06-2ubuntu16
  Candidate: 2.06-2ubuntu16
  Version table:
 *** 2.06-2ubuntu16 500
        500 http://us.archive.ubuntu.com/ubuntu lunar/main amd64 Packages
        100 /var/lib/dpkg/status

The zpool command does not have a -H flag (at least in Ubuntu 23.04).
This results in an error from the /etc/grub.d/10_linux_zfs script during update-grub.

The fix is to remove the -H flag and adjust the awk script to ignore the headline line (see diff).

$ sudo update-grub
Sourcing file `/etc/default/grub'
Sourcing file `/etc/default/grub.d/init-select.cfg'
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-6.2.0-24-generic
Found initrd image: /boot/initrd.img-6.2.0-24-generic
bad property list: invalid property '-H'
usage:
 get <"all" | property[,...]> <pool> ...

the following properties are supported:

 PROPERTY EDIT VALUES

 allocated NO <size>
 capacity NO <size>
 dedupratio NO <1.00x or higher if deduped>
 free NO <size>
 guid NO <guid>
 health NO <state>
 size NO <size>
 altroot YES <path>
 ashift YES <ashift, 9-13, or 0=default>
 autoexpand YES on | off
 autoreplace YES on | off
 bootfs YES <filesystem>
 cachefile YES <file> | none
 dedupditto YES <threshold (min 100)>
 delegation YES on | off
 failmode YES wait | continue | panic
 listsnapshots YES on | off
 version YES <version>
Found memtest86+ 64bit EFI image: /memtest86+x64.efi
Warning: os-prober will not be executed to detect other bootable partitions.
Systems on them will not be added to the GRUB boot configuration.
Check GRUB_DISABLE_OS_PROBER documentation entry.
Adding boot menu entry for UEFI Firmware Settings ...
done

Diffing the original against a patched (working) version:

$ diff 10_linux_zfs /etc/grub.d/10_linux_zfs
102c102,103
< local rel_pool_root=$(zpool get -H altroot ${p} | awk '{print $3}')
---
> # local rel_pool_root=$(zpool get -H altroot ${p} | awk '{print $3}')
> local rel_pool_root=$(zpool get altroot ${p} | awk 'NR > 1 {print $3}')