journal output from os-prober

Mar 29 18:50:52 ubuntu os-prober[3598]: debug: running /usr/lib/os-probes/10zvol-test on /dev/vda1
Mar 29 18:50:52 ubuntu os-prober[3601]: debug: running /usr/lib/os-probes/50mounted-tests on /dev/vda1
Mar 29 18:50:52 ubuntu 50mounted-tests[3621]: debug: mounted using GRUB fat filesystem driver
Mar 29 18:50:52 ubuntu 50mounted-tests[3622]: debug: running subtest /usr/lib/os-probes/mounted/05efi
Mar 29 18:50:52 ubuntu 05efi[3624]: debug: /dev/vda1 is a FAT partition (mounted by GRUB)
Mar 29 18:50:52 ubuntu 05efi[3632]: debug: /dev/vda1 partition scheme is gpt
Mar 29 18:50:52 ubuntu 05efi[3633]: debug: /dev/vda1 partition type is c12a7328-f81f-11d2-ba4b-00a0c93ec93b
Mar 29 18:50:52 ubuntu 05efi[3637]: debug: running subtest /usr/lib/os-probes/mounted/efi/10elilo
Mar 29 18:50:52 ubuntu 05efi[3640]: debug: running subtest /usr/lib/os-probes/mounted/efi/20microsoft
Mar 29 18:50:52 ubuntu 50mounted-tests[3645]: debug: running subtest /usr/lib/os-probes/mounted/10freedos
Mar 29 18:50:52 ubuntu 10freedos[3647]: debug: /dev/vda1 is a FAT partition (mounted by GRUB)
Mar 29 18:50:52 ubuntu 50mounted-tests[3650]: debug: running subtest /usr/lib/os-probes/mounted/10qnx
Mar 29 18:50:52 ubuntu 10qnx[3652]: debug: /dev/vda1 is not a QNX4 partition: exiting
Mar 29 18:50:52 ubuntu 50mounted-tests[3653]: debug: running subtest /usr/lib/os-probes/mounted/20macosx
Mar 29 18:50:52 ubuntu macosx-prober[3655]: debug: /dev/vda1 is not an HFS+ partition: exiting
Mar 29 18:50:52 ubuntu 50mounted-tests[3656]: debug: running subtest /usr/lib/os-probes/mounted/20microsoft
Mar 29 18:50:52 ubuntu 20microsoft[3658]: debug: Skipping legacy bootloaders on UEFI system
Mar 29 18:50:52 ubuntu 50mounted-tests[3659]: debug: running subtest /usr/lib/os-probes/mounted/30utility
Mar 29 18:50:52 ubuntu 30utility[3661]: debug: /dev/vda1 is a FAT partition (mounted by GRUB)
Mar 29 18:50:52 ubuntu 50mounted-tests[3666]: debug: running subtest /usr/lib/os-probes/mounted/40lsb
Mar 29 18:50:52 ubuntu 50mounted-tests[3668]: debug: running subtest /usr/lib/os-probes/mounted/70hurd
Mar 29 18:50:52 ubuntu 50mounted-tests[3670]: debug: running subtest /usr/lib/os-probes/mounted/80minix
Mar 29 18:50:52 ubuntu 50mounted-tests[3672]: debug: running subtest /usr/lib/os-probes/mounted/83haiku
Mar 29 18:50:52 ubuntu 83haiku[3674]: debug: /dev/vda1 is not a BeFS partition: exiting
Mar 29 18:50:52 ubuntu 50mounted-tests[3675]: debug: running subtest /usr/lib/os-probes/mounted/90linux-distro
Mar 29 18:50:52 ubuntu 50mounted-tests[3679]: debug: running subtest /usr/lib/os-probes/mounted/90solaris
Mar 29 18:50:52 ubuntu 50mounted-tests[3681]: debug: running subtest /usr/lib/os-probes/mounted/efi
Mar 29 18:50:52 ubuntu systemd[1]: var-lib-os\x2dprober-mount.mount: Deactivated successfully.
Mar 29 18:50:52 ubuntu os-prober[3689]: debug: running /usr/lib/os-probes/10zvol-test on /dev/vda2
Mar 29 18:50:52 ubuntu os-prober[3692]: debug: running /usr/lib/os-probes/50mounted-tests on /dev/vda2
Mar 29 18:50:52 ubuntu 50mounted-tests[3711]: debug: mounted using GRUB ext2 filesystem driver
Mar 29 18:50:53 ubuntu 50mounted-tests[3712]: debug: running subtest /usr/lib/os-probes/mounted/05efi
Mar 29 18:50:53 ubuntu 05efi[3714]: debug: /dev/vda2 is ext2 partition: exiting
Mar 29 18:50:53 ubuntu 50mounted-tests[3715]: debug: running subtest /usr/lib/os-probes/mounted/10freedos
Mar 29 18:50:53 ubuntu 10freedos[3717]: debug: /dev/vda2 is not a FAT partition: exiting
Mar 29 18:50:53 ubuntu 50mounted-tests[3718]: debug: running subtest /usr/lib/os-probes/mounted/10qnx
Mar 29 18:50:53 ubuntu 10qnx[3720]: debug: /dev/vda2 is not a QNX4 partition: exiting
Mar 29 18:50:53 ubuntu 50mounted-tests[3721]: debug: running subtest /usr/lib/os-probes/mounted/20macosx
Mar 29 18:50:53 ubuntu macosx-prober[3723]: debug: /dev/vda2 is not an HFS+ partition: exiting
Mar 29 18:50:53 ubuntu 50mounted-tests[3724]: debug: running subtest /usr/lib/os-probes/mounted/20microsoft
Mar 29 18:50:53 ubuntu 20microsoft[3726]: debug: Skipping legacy bootloaders on UEFI system
Mar 29 18:50:53 ubuntu 50mounted-tests[3727]: debug: running subtest /usr/lib/os-probes/mounted/30utility
Mar 29 18:50:53 ubuntu 30utility[3729]: debug: /dev/vda2 is not a FAT partition: exiting
Mar 29 18:50:53 ubuntu 50mounted-tests[3730]: debug: running subtest /usr/lib/os-probes/mounted/40lsb
Mar 29 18:50:53 ubuntu 50mounted-tests[3732]: debug: running subtest /usr/lib/os-probes/mounted/70hurd
Mar 29 18:50:53 ubuntu 50mounted-tests[3734]: debug: running subtest /usr/lib/os-probes/mounted/80minix
Mar 29 18:50:53 ubuntu 50mounted-tests[3736]: debug: running subtest /usr/lib/os-probes/mounted/83haiku
Mar 29 18:50:53 ubuntu 83haiku[3738]: debug: /dev/vda2 is not a BeFS partition: exiting
Mar 29 18:50:53 ubuntu 50mounted-tests[3739]: debug: running subtest /usr/lib/os-probes/mounted/90linux-distro
Mar 29 18:50:53 ubuntu 50mounted-tests[3743]: debug: running subtest /usr/lib/os-probes/mounted/90solaris
Mar 29 18:50:53 ubuntu 50mounted-tests[3745]: debug: running subtest /usr/lib/os-probes/mounted/efi
Mar 29 18:50:53 ubuntu systemd[1]: var-lib-os\x2dprober-mount.mount: Deactivated successfully.
Mar 29 18:50:53 ubuntu os-prober[3753]: debug: running /usr/lib/os-probes/10zvol-test on /dev/vda3
Mar 29 18:50:53 ubuntu os-prober[3756]: debug: running /usr/lib/os-probes/50mounted-tests on /dev/vda3
Mar 29 18:50:53 ubuntu 50mounted-tests[3775]: debug: mounted using GRUB btrfs filesystem driver
Mar 29 18:50:53 ubuntu 50mounted-tests[3776]: debug: running subtest /usr/lib/os-probes/mounted/05efi
Mar 29 18:50:53 ubuntu 05efi[3778]: debug: /dev/vda3 is btrfs partition: exiting
Mar 29 18:50:53 ubuntu 50mounted-tests[3779]: debug: running subtest /usr/lib/os-probes/mounted/10freedos
Mar 29 18:50:53 ubuntu 10freedos[3781]: debug: /dev/vda3 is not a FAT partition: exiting
Mar 29 18:50:53 ubuntu 50mounted-tests[3782]: debug: running subtest /usr/lib/os-probes/mounted/10qnx
Mar 29 18:50:53 ubuntu 10qnx[3784]: debug: /dev/vda3 is not a QNX4 partition: exiting
Mar 29 18:50:53 ubuntu 50mounted-tests[3785]: debug: running subtest /usr/lib/os-probes/mounted/20macosx
Mar 29 18:50:53 ubuntu macosx-prober[3787]: debug: /dev/vda3 is not an HFS+ partition: exiting
Mar 29 18:50:53 ubuntu 50mounted-tests[3788]: debug: running subtest /usr/lib/os-probes/mounted/20microsoft
Mar 29 18:50:53 ubuntu 20microsoft[3790]: debug: Skipping legacy bootloaders on UEFI system
Mar 29 18:50:53 ubuntu 50mounted-tests[3791]: debug: running subtest /usr/lib/os-probes/mounted/30utility
Mar 29 18:50:53 ubuntu 30utility[3793]: debug: /dev/vda3 is not a FAT partition: exiting
Mar 29 18:50:53 ubuntu 50mounted-tests[3794]: debug: running subtest /usr/lib/os-probes/mounted/40lsb
Mar 29 18:50:53 ubuntu 50mounted-tests[3796]: debug: running subtest /usr/lib/os-probes/mounted/70hurd
Mar 29 18:50:53 ubuntu 50mounted-tests[3798]: debug: running subtest /usr/lib/os-probes/mounted/80minix
Mar 29 18:50:53 ubuntu 50mounted-tests[3800]: debug: running subtest /usr/lib/os-probes/mounted/83haiku
Mar 29 18:50:53 ubuntu 83haiku[3802]: debug: /dev/vda3 is not a BeFS partition: exiting
Mar 29 18:50:53 ubuntu 50mounted-tests[3803]: debug: running subtest /usr/lib/os-probes/mounted/90linux-distro
Mar 29 18:50:53 ubuntu 50mounted-tests[3807]: debug: running subtest /usr/lib/os-probes/mounted/90solaris
Mar 29 18:50:53 ubuntu 50mounted-tests[3809]: debug: running subtest /usr/lib/os-probes/mounted/efi