Acronis Secure Zone is a secure partition on a disk of the backed-up machine. It can store backups of disks or files of this machine.

Is Acronis Secure Zone included in Entire Machine backup?

The Acronis Secure Zone partition is skipped during Entire Machine backup if at least one of the backup locations (primary or secondary) specified in the protection plan is Acronis Secure Zone. This is required to avoid recursion.

In case the backup location is external (on a network share, Acronis Cloud etc), then Acronis Secure Zone is included in Entire Machine backup.