I found

  cat /etc/apt/apt.conf.d/90_zsys_system_autosnapshot
  // Takes a snapshot of the system before package changes.
  DPkg::Pre-Invoke {"[ -x /usr/libexec/zsys-system-autosnapshot ] && /usr/libexec/zsys-system-autosnapshot snapshot || true";};

  // Update our bootloader to list the new snapshot after the update is done to not block the critical path
  DPkg::Post-Invoke {"[ -x /usr/libexec/zsys-system-autosnapshot ] && /usr/libexec/zsys-system-autosnapshot update-menu || true";};

but how would I get this to not snapshot , say /home/Downloads .. make that its own zpool?