Disclaimer/preface: I don't know all that much about MacOS.
I was investigating why my Time Machine (and later, borgbackup'ed tmutil localsnapshot
s) incremental backups were larger than I expected -- around 1-7 GB worth of changes per day.
I found this out after I had set up Time Machine backups to a TrueNAS CORE machine and had set up regular snapshots of the Time Machine ZFS dataset:
# zfs list -t snapshot -o space -r /mnt/vault/delorean/philsnow | head