How to mount System Volume using APFS snapshot

Question

I am not able to mount System Volume (root) using APFS. I only see my Data Volume.

$ mkdir /tmp/snapshotbackup_root
$ mount_apfs -s com.apple.TimeMachine.2019-10-29-174444.local / /tmp/snapshotbackup_root
$ df -h /tmp/snapshotbackup_root
Filesystem                                                   Size   Used  Avail Capacity iused      ifree %iused  Mounted on
com.apple.TimeMachine.2019-10-30-121116.local@/dev/disk1s3  223Gi   97Gi  115Gi    46% 1904164 2340358076    0%   /private/tmp/snapshotbackup_root

As you can see, it only mounts /dev/disk1s3, I am unable to mount the System Volume which is /dev/disk1s1.

$ mount_apfs -s com.apple.TimeMachine.2019-10-29-174444.local@/dev/disk1s1 / /tmp/snapshotbackup_root
mount_apfs: volume could not be mounted: No such file or directory

Time Machine can mount it as seen below

$ df -h "/Volumes/com.apple.TimeMachine.localsnapshots/Backups.backupdb/MacBook Pro 840 G3/2019-10-29-174444/OSX"*
Filesystem                                                   Size   Used  Avail Capacity iused      ifree %iused  Mounted on
com.apple.TimeMachine.2019-10-29-174444.local@/dev/disk1s1  223Gi   10Gi  115Gi     9%  481433 2341780807    0%   /Volumes/com.apple.TimeMachine.localsnapshots/Backups.backupdb/MacBook Pro 840 G3/2019-10-29-174444/OSX
com.apple.TimeMachine.2019-10-29-174444.local@/dev/disk1s3  223Gi   96Gi  115Gi    46% 1899738 2340362502    0%   /Volumes/com.apple.TimeMachine.localsnapshots/Backups.backupdb/MacBook Pro 840 G3/2019-10-29-174444/OSX – data

Answer 1

mount_apfs -s com.apple.TimeMachine.2019-10-29-174444.local /dev/disk1s1 /tmp/snapshotbackup_root